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huhcwJ Phvs.S2(4), 475-478(2008) 
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English

Notes for Contributors

Indian J. Plm. 82 (5), 491 -493 (200S) 
HMAi lit 
PI¥H0 
Vol.82 • No. 5 • May 2008 
(CONTENTS 
Proceedings (Parti) of the ffh Biennial Conference of the Physics Academy 
of the North East (PANE) held at Department of Physics, Gauhati University, 
Guwahati-781 014, Assam, India during March 1-2, 2007. 
Front Title 485 
Advisory Board and Editors 487-488 
Rom Editor's Desk 489 
Front Contents 491-493 
Foreword 
DILIP KUMAR CHOUDHURY AND BUDDHADEB BHATTACHARJEE 495-496 
Use of low energy accelerators 
AMITROY 497-504 
Invited Talk 
Fragility of Pb modified germanium chalcogenide glasses 
A SRINIVASAN AND A K PATTANAIK 505-511 
Bianchi type-1 string cosmology with a scalar field 
K K B A R U A H 513-517 
The space distribution of QSOs 
IROM ABLU MEITEI AND K YUGINDRO SINGH 519-522 
| Cont'd on next page j 
492 Contents 
The rapid neutron capture process in an explosive astrophysical 
environment 
RULEE BARUAH, KALPANA DUORAH AND H L DUORAH 523-529 
Raychaudhuri equation, big bang and accelerating universe 
K D KRORI, SABITA DUTTA, KANIKA DAS AND CHANDRA REKHA MAHANTA 531-537 
Studies on water vapour droplets using a laser based air quality 
monitoring system 
D DAS, G A AHMED AND A CHOUDHURY 539-544 
Correlation distance of ionospheric total electron content in the 
Indian low latitude region 
RASHMI REKHA BORAH, K BHUYAN AND P K BHUYAN 545-550 
Dirac and Infeld-Hull ladder operator methods for a modified 
oscillator potential 
O BABYNANDA DEVI AND C AMUBA SINGH 551-560 
Algebraic approach to analyze the vibrational spectra of 
tetrahedral molecules 
JOYDEEP CHOUDHURY, NIRMAL KUMAR SARKAR AND 
RAMENDU BHATTACHARJEE 561-565 
A T-matrix approach for morphological characterization of spherical 
nanoparticles using laser 
ANKUR GOGOI AND GAZI AMEEN AHMED 567-570 
Solvent dependent Raman anisotropic bandwidth study in carbonyl 
containing molecule: role of van der Waals' volume in 
intermolecular interactions 
TH GOMTI DEVI AND K KUMAR 571-575 
Performance of thermally deposited polycrystalline Ge-thin film 
transistors with a copper interlayer fabricated on glass substrates 
P GOGOI, K KONWAR AND B BAISHYA 577-583 
Effect of wavelength and intensity of illumination on the photoelectronic 
properties of CdSe thin films 
K SARMAH, R SARMA AND H L DAS 585-594 
A study of current - voltage characteristics of ITO/(p)Si heterojunctions 
S CHALIHA, M N BORAH, P C SARMAH AND A RAHMAN 595-601 
Contents 493 
Study of critical current density from ac susceptibility measurements 
in (LavxYx)2Ba2CaCu5Oz superconductors 
P K NAYAK AND S RAVI 603-610 
Synthesis of lithium zinc ferrite powders by citrate precursor gel 
formation method 
IBETOMBI SOIBAM, SUMITRA PHANJOUBAM, H BASANTKUMAR SHARMA 
AND H N K SARMA 611-614 
A numerical model for studying glass dissolution in water 
SBSANTRAANDS RANJITACHANU 615-620 
An analysis of self-similarity in quark and gluon densities at small x 
D K CHOUDHURY AND RUPJYOTI GOGOI 621-625 
Programmable trigger circuit for UHE cosmic ray detection by mini-
array method: simulation with VHDL 
NAYANMONI SAIKIA, BANTY TIRU, DUDUMONI HANDIQUE, P K BORUAH 
ANDKBORUAH 627-631 
Emission characteristics of intermediate mass fragments on the residual 
part of the projectile nucleus 
BDEBNATH, R TALUKDAR AND B BHATTACHARJEE 633-638 
Forthcoming Publications 63JH540 
Notes for Contributors 641-644 
Our Special Publications 645-646 


Front Contents

Gogoi, P

Konwar, K

Baishya, B

Indian J Phvs. 82 (5), 577-583 (2008) 
um 
Performance of thermally deposited polycrystalline 
Ge-thin film transistors with a copper interlayer 
fabricated on glass substrates 
P Gogoi*, K Konwar and B Baishya 
Department of Physics Dibrugarh University, 
Dibrugarh 786 004 Assam India 
E-mail paragjyoti _g(« rediffmail com 
Abstract The performance of Ge- TFTs with a copper interlayer in the channel region is presented TFTs 
are fabricated in staggered electrode structure on perfectly cleaned glass substrates using thermal evaporation 
process with rare earth oxide Dy203 as gate insulator The TFTs are annealed at 370°C under high vacuum The 
TFTs exhibit a mobility of 0 646 cmzV 's 'and threshold voltage of 3 V The characteristics and some electrical 
parameters of the TFTs with copper interlayer are evaluated using Weimer's model [Phys Thin Films 2 149 
(1964)] and characterized by Levmson era/ [J Appl Phys 53 1193 (1982)] model The various electrical 
parameters of the TFTs are compared with those of Ge - Dy^O, TFTs fabricated without copper interlayer 
Keywords Poly Ge-TFT, copper interlayer, Dy203 
PACS Nos. 73 61 Cw, 73 40 Qv 
1. Introduction 
In large area electronics circuits, TFTs are widely used as driving devices. Especially in 
active matrix liquid crystal displays (AMLDs), TFTs are used as pixel transistors [1]. In 
the grain boundaries of a polycrystalline semiconductor, there are large numbers of defects 
due to incomplete atomic bonding or the dangling bonds due to which potential barriers 
are established in the grain boundaries .The grain boundary potential barriers in 
polycrystalline TFTs impede the motion of charge carriers from one crystallite to another 
and hence decrease the mobility [2]. The passivation of grain boundary states by atomic 
hydrogen is a well-established technique which is employed to reduce the grain boundary 
potential barrier in poly-Si [3]. It has been reported that, in polycrystalline Si, some of the 
dangling bonds in the grain boundanes can be completed by means of hydrogen passivation 
Corresponding Author 
©2008IACS 
578 P Gogoi, K Konwar and B Baishya 
in which atomic hydrogen ties up with most of the dangling bonds and reduce the gram 
boundary potential barrier [4]. Copper passivation of dislocations in polycrystalline silicor 
reduces the potential barrier height at the grain boundaries [5]. 
Rare earth oxides play an important role in thin film transistors as gate insulators due 
to their high chemical stability, high dielectric constant and high resistivity [6-8]. 
Levinson et al [9] have proposed a model based on the grain boundary trapping for 
characterization of polycrystalline thin film transistors. Using this model the TFTs fabricated 
with a coper interlayer have been characterized and some important parameters such a^  
trap density (A/,), critical donor density (Nd) and crystallite size (L) are evaluated These 
parameters are compared with the TFTs fabricated without copper interlayer. 
2. Experimental details 
2.1. Fabrication of the TFTs: 
The TFTs were fabricated using thermal evaporation process in high vacuum better ther 
4x10"6 torr in staggered electrode structure on glass substrates. Aluminium was deposited 
first as source and drain electrodes. A channel of 50 /urn length was produced with thf 
help of a wire grill, fixed on the mask. A 1050A channel layer was formed between the 
source-drain gap by deposition of Ge (510 A), Cu (20 A) and Ge (520 A) layers in steps 
The Ge/Cu/Ge layers are deposited at substrate temperature of 250° C with a deposition 
rate of 0.5 As"1. A layer of Dy203 of thickness 715 A was deposited as gate insulator 
over the Ge/Cu/Ge layers. Finally, a layer of Al was deposited on the oxide layer as gate 
electrode. The fabricated TFTs were annealed in high vacuum at 370° C for 5 hours 
Ge- Dy203 TFTs without copper interlayer have also been fabricated with the similar 
procedure as mentioned above. These TFTs are also annealed to a temperature of 370' C 
for 5 hours. 
2.2. Measurements: 
The film thicknesses were measured by multiple beam interference method. The resolution 
of the thickness measurement set-up is ± 10 A. The gate capacitance was measured 
using auto computer LCR sortester (APLAB, Model 4912). The drain current, drain voltage 
were measured using the digital nanoammeters and digital multimeters. 
3. Results and discussions 
3.1. Electrical characteristics: 
The characteristics depicting the variation of drain current (ld) with drain voltage (Vd) at 
constant gate voltage (Vg) for the TFTs fabricated with a copper interlayer is shown in 
Figure 1. From Figure 1 it is noted that the TFTs with copper interlayer show well-modulated 
ld vs. Vd characteristics at constant gate voltage (Vg). Figure 2 shows the field effect 
characteristics of the TFTs at drain voltage Vd = 8V. 
performance of thermally deposited polycrystalline Ge-thin film transistors etc 579 
0 1 2 3 4 5 6 7 8 9 
Drain voltage (Vj) in volt 
Figure 1. Id - Vd curves of the TFTs with 
copper interlayer 
The electrical parameters of TFTs are calculated using the following expressions [10]. 
Transconductance (gm) 
\ H 
-13 -« 3 
\ t 111 
-13 -11 - 0 - 7 5 3 
•T 
* "^  
2 7 
wil l 
• 100 
00 
80 "$ 
70 -E 
60 ^? 
£ 
8 
cu
rr
en
t 
c 
20 Q 
„ j n 
1 
Gate voltage (V\) in volt 
Figure 2. Id - V curves of the TFTs with 
copper interlayer. The insert 
variation of \1r1 at different Vt1 
shows the 
0,77 = 
W 
Vrt=cons/ 
^j^FETC0XVd (1) 
where Cox is the gate capacitance per unit area, w is the channel width, / is the channel 
length, Vd is the drain voltage and / j F f r is the field effect mobility. 
Output drain resistance 
dV„ 
rd = lL (2) 
Vg^r const 
amplification factor 
V = 9m*rd 
and gain-bandwidth (G.Sw) product 
G.Bw = 9m 
2nCt 
(3) 
(4) 
ox 
The mobility of the devices is estimated using eq. (1). The calculated values of output 
drain resistance {rd), transconductance ( g j , amplification factor {v), mobility (^FE7)and 
the gain-bandwidth product {G.BW) of the TFTs are presented in Table 1. 
580 P Gogoi, K Konwarand B Baishya 
Table 1 Comparison of some parameters of the TFTs with copper interlayer and without copper mteriayer 
Type of Output resistance Transconductance Amplif ication Mobility Gam bandwidtr 
TFTs rH gm factor M M^ product G B* 
(mho) ( c n r ^ W ) (KHz) (ohm) 
with 
copper 
interlayer 
without 
copper 
interlayer 
0 125 X 106 3 86 X 10 6 
89 29 X 106 0 0083 X 10 6 
0 49 0 646 1 31 X 10 
0 70 1 44 X 103 9 35 X10 
3 2 Characterization of the TFTs 
The Ge semiconductor used in this investigation is polycrystalline in nature and usually 
contains many grain boundaries in the conducting channel, which interrupts the mean 
free path of the charge carriers and acts as trapping centers [11] Hence, grain boundary 
trapping model proposed by Levinson et al [9] is used to charactenze the TFTs The 
expression for drain current ld of the TFTs with polycrystalline materials is given by-
ld = wfjb-
V« 
C0XVgexp\ 
~q3Nt2t 
8ckTC0XVg (5i 
where, w is the channel width, / is the channel length, v
 b is the field effect mobility C 
is the insulator capacitance per unit area, Nt is the trap density per unit area and / is 
the thickness of the semiconductor film 
From eq (5), it is evident that, the plot of In (ld/Vg) vs(1A/g) is a straight line (Figure 
3) From the slope of this straight line, Nt can be estimated The deviation from lineantv 
24 
18 1 
1 2 i 
06 1 
n -i 1 1 1 1 1 i 
0 01 02 03 04 05 06 
Figure 3. Plot of In (ld/ vy vs ( 1 / VJ for Ge-Dy203 TFTs with a copper interlayer 
performance of thermally deposited polycrystalltne Ge-thm film transistors etc 581 
,n Figure 4 occurs, when / y / = Nd\ where Nq= (Cox/q) Vg is the gate induced carrier 
concentration and Nd is the critical donor density The crystallite size L can be calculated 
from Nd' = Nt/L The values of Nt Nd\ and L obtained for Ge-Dy203TFTs with a copper 
interlayer are presented in Table 2 
Table 2 Comparison of trap density (Nt)t critical donor density (/V,) and crystallite size (L) of the 
fabricated devices with copper interlayer and without copper interlayer 
Type of device 
Gc D y p 3 with 
copper interlayer 
Ge Dy203 without 
Cu interlayer 
Trap density 
Nt (cm2) 
3 61 X 1011 
1 86 X 101? 
Critical donor 
density N(i (cm 3) 
081 X 1017 
1 61 X 1017 
Crystallite 
size L (A) 
451 25 
121 
3 3 Comparison of the parameters of the TFTs fabricated with copper interlayer and without 
copper interlayer 
The dram current (ld) vs dram voltage (Vd) characteristics of the TFTs, without copper 
interlayer are shown in Figure 4 Comparing Figures 1 and 4 it is seen that the family of 
drain current of the TFTs with copper interlayer exhibit higher dram current than the TFTs 
without copper interlayer This is due to their higher mobility and lower threshold voltage 
Figure 5 shows the field effect characteristics at drain voltage Vd - 8V for the TFTs 
without copper interlayer The threshold voltage (VT) of the TFTs with copper interlayer and 
without copper interlayer have been evaluated by plotting vld vs gate voltage (Vg) at constant 
drain voltage (Vd), which are shown in the insert of Figures 2 and 5, respectively, and are 
• ^ 
•^  
t 
•J 
c 
-
0 12 
0 1 
0 08 
0 06 
0 04 
0 02 
0 1 
C ) 1 ' 2 
Dram 
3 4 5 
voltage (Vj) 
6 
\ 
7 
in volt 
nyi 
ml 
•^*j±L 
7\1 
j y \ 
2 U 
/,= o^l 
8 9 
V 
* 4 
tJ • * t J 7 
V in volt 
0 1? 
0 1 
noe ~ 
0D2 
Q 
13 11 9 7 5 3 1 
Gate voltage (Vj in volt 
Figure 4. Id - Vd curves of the TFT's without 
copper interlayer 
Figure 5. Id - Vg curves of the TFT's without 
copper interlayer The insert shows variation 
of V/d at different V 
582 P Gogoi, K Konwar and B Baishya 
found to be 3V for copper interlayer and 6V for without copper interlayer. The estimated 
values of the electrical parameters of the TFTs without copper interlayer are also presented 
in Table 1. The value of trap density (A/,), critical donor density (Nd) and crystallite size 
(L) of the TFTs without copper interlayer are also evaluated and these are presented m 
Table 2. 
The mobility of TFTs with copper interlayer and without copper interlayer are found as 
0.646 cm2V"1s1 and 0.4x103 cm2V1s"1 respectively which are shown in Table 1. The 
enhance mobility of the TFT's with copper interlayer is due to the fact that, during thf-
heat treatment, the grain boundary states in the case of poly- Ge TFTs are passivated by 
copper in Ge. During the passivation, copper atom diffuses along the grain boundary 
and completes some of the open bonds (dangling bonds). Consequently the interface 
states density drops and the potential barrier is lowered. The resulting effect is that the 
poly-Ge electrically progresses towards single crystal Ge characteristics, yielding higher 
mobility. The TFT without copper interlayer is also heated to the temperature 370° C, but 
it does not show enhance mobility as that of the TFT fabricated without copper interlayer 
This implies that diffusion of Al in Ge does not take place though the TFTs are heated to 
a temperature of 370° C. 
4. Conclusion 
Comparing the characteristics and the electrical parameters it is seen that the performance 
of the TFTs fabricated with copper interlayer is better that than of the TFTs fabricated 
without copper interlayer. The TFTs with copper interlayer exhibit higher mobility than the 
TFTs without copper interlayer. It is observed that the threshold voltage (VT) is significantiv 
improved in case of TFTs with copper interlayer. The other electrical parameters such as 
output resistance (rd)} transconductance (gm), trap density (A/,), critical donor density {N0'j 
and crystallite size (L) are also found to be better in case of TFTs with copper interlayer 
but amplification factors (n ) are comparable for both types of TFTs. From this observation 
it may also be concluded that TFTs with Dy203 could be realized. 
Acknowledgment 
Authors P Gogoi and K Konwar are grateful to the Govt, of Assam for financial 
assistance 
References 
[1] A W Wang and K C Saraswat IEEE Transaction on Electron Devices 47 5 1035 (2000) 
[2] S Y W John J. Appl. Phys. 46 5247 (1975) 
[3] C H Seager and D S Ginley J. Appl. Phys. 52 1005 (1981) 
[4] S D S Malhj , H Shichijo, S K Banarjee, R Sundaresan, M Elahy, G P Polack , W F Richardson 
A H Shah, L R Hite, R H Womack, P K Chatterjee and H Wailam IEEE Transaction on Electron 
Devices 32 2 258 (1985) 
[5) J G Lee and S R Morrison J. Appl. Phys. 64 6679 (1988) 
Performance of thermally deposited polycrystalline Ge-thin film transistors etc 
[6] P K Deka and B Baishya Thin Solid Films 112 L5 (1984) 
[7] P Singh and B Baishya Thin Solid Films 141 179 (1986) 
[8] P Singh and B Baishya Thin Solid Films 47 25 (1987) 
(9) J Levinson, F R Shepherd, P J Scanlon, W D Westwood, G Este and M Rider 
Phys. 53 1193 (1982) 
MO] P K Weimer Phys Thin Films 2 149 (1964) 
|11] J C Anderson Thin Solid Films 36 (1976) 299 


Performance of Thermally Deposited Polycrystalline Ge-Thin Film Transistors with a Copper Interlayer Fabricated on Glass Substrates

Chaliha, S

Borah, M N

Sarmah, P C

Rahman, A

InJiaiiJ. WIVA.82(5),595-601 (2008) 
A study of current -voltage characteristics of ITO/(p)Si 
heterojunctions 
S Chaliha1*, M N Borah2, P C Sarmah* and A Rahman'1 
department of Physics Bahona College Jorhat 785 101 Assam India 
-'Department of Physics D R College Golaghal 785 621 Assam India 
'Department of Electronics Regional Research Laboratory, Jorhat-785 006 Assam India 
department of Physics, Gauhati University Guwahati 781 014 Assam India 
L mail sumbitcf" gmail com 
Abstract A IT0/(p)Si heterojunction was fabricated by depositing Indium Tin Oxide (ITO) thin films onto 
well cleaned p-type silicon wafer by thermal evaporation method from pure ITO powder at substrate temperature 
5^JK The different diode parameters were calculated from the current-voltage characteristics of the junctions 
Thp diode ideality factor was found to be greater than 1 and the diode had high series resistance The I V 
characteristics under illumination showed poor photovoltaic effect of the junction Large series resistance high 
defect density and presence of interfacial layer are thought to be the main causes for higher value diode ideality 
factor and poor photovoltaic conversion efficiency 
Keywords Indium Tin Oxide thermal evaporation, diode ideality factor, photovoltaic effect 
PACS Nos. 73 40 Lq, 81 15 Ef, 73 50 Pz 
1. Introduction 
Indium Tin Oxide (ITO) is a degenerate semiconductor having band gap of approximately 
3 6 eV This high conducting material with high transparency in visible region is a good 
transparent electrical conductor ITO has been used as a transparent electrode in advanced 
optoelectronic devices such as solar cells, light emitting and photo diodes, photo transistors 
and liquid crystal displays Thin films of Indium Tin Oxide have been reported to be 
prepared by variety of techniques such as spray pyrolysis, sputtering, reactive evaporation, 
pulsed laser deposition, thermal evaporation method etc [1-7] The property of a film 
depends on the method of preparation. Studies of ITO-Si structures have been reported 
by some workers where the ITO films were deposited by rf sputtering [3] or spray pyrolysis 
method [1, 2]. However, not much information have been obtained for junctions of ITO film 
Corresponding Author 
©2008IACS 
596 S Chaliha, M N Borah, P C Sarmah and A Rahman 
prepared by thermal evaporation directly onto the Si substrate. The evaluation of diode 
parameters provides a useful guidance for further characterizing this device structure i» 
the present investigation, ITO films were deposited by thermal evaporation method frorr 
ITO powder on silicon wafer to form ITO/(p)Si heterojunction and their current-voltage (j-v 
characteristics were studied. Different electrical parameters of the junction calculated frop 
these characteristics have been presented in this paper. 
2. Experimental 
The ITO thin films of thickness about 2000 A were prepared by thermal evaporation j< 
pure Indium Tin Oxide powder (99.999%) in a vacuum better than 10"5 Torr, at a deposition 
rate of about 1A /sec. ITO films were vacuum deposited on chemically cleaned glasc 
substrates for studying their electrical and optical properties. During deposition Uu 
substrates were kept at a temperature of 523K. For the preparation of a heterojunction 
initially, Al electrodes were vacuum deposited on one side of (p)Si wafers to make ohmi 
contacts and then ITO films were deposited on the other side, thus making ITO/(p)Si-A< 
structures. The specifications of Si wafers used were: boron-doped (p-type), orientation 
(100), resistivity 10-20 ohm cm, thickness 50000-55000 A and area 1.5x1.5 cm2. Before 
deposition of counterelectrodes for measurement, ITO films as well as the junction structures 
were annealed for one hour at 350K temperature. This was done in order to improve the 
conductivity and transparency of the ITO films as reported in our earlier study [71 
Countertoelectrodes of Al were vacuum deposited over ITO films for making ohmic contacts 
to ITO films. Thus structures of the type AI-ITO/(p)Si-AI were obtained. For electrica, 
study of ITO film, a gap type structure was formed by depositing Al electrodes on two 
ends of the thin films keeping a gap between them. The conductivity was measured troir 
l-V characteristics of the ITO film. The thickness of the films was measured by multiple 
interference method [8], The optical transmittance was studied with the help of a i n -
visible spectrophotometer (Cary 300, Varian, Australia). For all current-voltage and 
photovoltaic measurements, the junctions were mounted on a sample holder kept inside a 
specially designed metal chamber evacuated up to 10"2 Torr using a rotary pump For 
current measurement an Electrometer (Keithley model 6514, USA) was used. For J-v 
measurement under illumination, the junction in the chamber was illuminated through a 
glass window using white light from a tungsten-halogen lamp. The details of experimental 
arrangement has been reported elsewhere [9, 10]. The C-V measurements were performed 
on the junctions at room temperature, using a digital Autocompute 4-CR-Q (Aplab-4910) 
meter. 
3. Results and discussion 
The electrical conductivity of the prepared ITO films was found around 1.5x10'2 Q1cm 
with sheet resistivity of 3375 KQ/square. The optical transmittance of a typical ITO film in 
the wavelength from 300nm to 600nm after annealing is shown in Figure 1. From Figure 
it is seen that the optical transmittance of the film is about 74% at wave length of 
550nm. 
A study of current-voltage characteristics oflTO/(p) Si heterojunctions 597 
The J-V characteristics of a few typical ITO/(p)Si junctions in dark have been shown in 
Figure 2. The curves exhibited rectifying nature of a Schottky diode in the forward direction. 
Under the forward bias the current increases exponentially with voltage In reverse bias 
8 0 
6 0 
; 4 0 
2 0 
3 0 0 400 500 
wave length (nm) 
600 
Figure 1. Transmittance vs wavelength of ITO films of thickness 2000A 
400 
- 2 5 
Figure 2. J-V characteristics of three ITO-(p)Si junctions of different cross-sectional area at room 
temperature in dark 
the current increases slowly with voltage and did not show any tendency of saturation. 
The J-V characteristics followed the standard diode equation [11] 
J = J0 exp(gV/nfr7")[l - exp(-qV/kT)] 0) 
where, J is the current density of a diode for bias voltage Vat temperature T (K), n is the 
diode ideality factor, J0 is the saturation current density and other quantities has their 
usual meanings. 
598 S Chaliha, M N Borah, P C Sarmah and A Rahman 
Figure 3 shows ln[J/{1-exp(-qV/kT)}] vs V/ plots for a few typical ITO-(p)Si junctions m 
dark at room temperature. At higher forward voltage (> 0.6V) the InJ-l/ plots of the junctions 
have been observed to deviate from linearity. This is due to presence of series resistance 
(Rs) associated with the neutral region of the diode. For this series resistance, the current 
of the diode is proportional to exp[g(t/-/f?s)//cT-1], instead of obeying the ideal condition 
[12]. At low voltage, the current is less, and hence the diode current can be characterized 
by equation (1). The ideality factor (n) calculated from the slopes and the saturation 
current density (J0) calculated from the intercept of the linear region of the plots (Figure 
3) for three junctions are tabulated in Table 1. The ideality factor have been found to be 
greater than the values reported earlier for this type of diode prepared by depositing ITO 
layer by other methods [2, 3]. However diode ideality factor can be affectively improved by 
controlling the deposition parameters which will be discussed later. The reverse current 
does not saturate and shows the tunneling probability due to lowering of potential barrier 
on application of bias. 
-10 
• 
Q. 
<P-16 
£ - 1 8 
-20 
0.2 0.4 0.6 0.8 
V (volt) 
Figure 3. ln[J/{1-exp(-gWfc7)}] vs V curves of three ITO-(p)Si junctions at room temperature in dark 
Various factors were found to affect J-1/characteristics and diode ideality factor in the 
present case. These curves depend on electrode area of the junctions. The existence of 
an interfacial layer of oxide on the surface of the silicon, image force lowering of the 
barrier heights, electron and hole recombination in the depletion region, tunneling effect 
Table 1. Diode parameters of three typical ITO-(p)Si junctions at room temperature (303K), 
Junction Junction Ideality Saturation Barrier Series Open Short-circuit Fill 
area factor current height resistance circuit current factor 
(cm2) n density 4>(eV) R8 (K£2) voltage density 
J0(nA/cm2) (mV) (mA/cm2) 
A 0.030 4.76 3 0.593 17 475 0.48 0.266 
B 0.034 5.134 9 0.581 20 450 0.60 0.224 
C 0.038 5.2 15 0.575 23 435 0.75 0.212 
A study of current-voltage characteristics oflTO/(p) Si heterojunctions 599 
are the main reasons for the ideality factor (n) to be greater than unity. The effect of 
interfacial layer also contributed to high reverse current. 
The series resistance estimated from InJ vs V plots (not shown here) of the diodes 
are tabulated in Tablel. In the present case, the large value of series resistance is 
contributed by the high sheet resistance of ITO layer and the resistance offered by the 
junction (interfacial oxide layer). 
0 1 0 3 
Vr (volt) 
0 5 
Figure 4. C 2 vs V(reverse) plots for three ITO-(p)Si junctions at room temperature in dark 
The C"2-l/ plots for three junctions have been drawn at frequency 1KHz (Figure 4) for 
reverse bias. The carrier concentration and the built-in potential at the junction are estimated 
from the slope and intercept of C2-Vplots of the junction under reverse bias condition 
using the following relation [13] 
c-2=(2(i^-i/-/cr/^ 
qcNc (2) 
Here Vbl is the built in potential at zero bias which is equal to VfkT/q, where Vf is 
the negative intercept on the Vr axis and r is the permittivity of Si. The carrier concentration 
evaluated from the slopes is of the order of 1015 cm3. The barrier height is calculated 
from the measured value of Vbl from 4>b = qVbt +(EF-EV), where E F - Ev is the difference 
between valence band energy and Fermi energy, and depends upon the doping density in 
the following way, 
&-£„ = kT In N. (3) 
where Nv is the effective density of states in valence band. The barrier height obtained for 
these junctions is nearer to 0.6 eV, which is less than the barrier height obtained by 
Vasu et al [2] by controlling the thickness of interfacial oxide layer. 
600 S Chaliha, M N Borah, P C Sarmah and A Rahman 
The ITO-(p)Si junctions were studied for its photovoltaic performances. Figure 5 shows 
J-V curves of three typical junctions when illuminated by light of intensity 50 mW/cm: 
Nearly linear nature of the curves implies the existence of a large series resistance. Table 
1 shows the open-circuit voltage, short-circuit current and fill-factor of a typical junction 
Very low photovoltage ( -450 mV) has been observed in the junctions due higher value 
diode ideality factor as reported by Mirzah et al [3]. The high defect density present with 
thermally evaporated ITO layer, presence of interfacial layer, presence of high series 
resistance and low conductivity of ITO layer are responsible for poor photovoltaic performance 
of the device. 
0.2 
100 0 
c^-0.2 
E 
.o 
< 
£-0.4 
-0.6J 
B 
c / / • V(mV) 
100 200 300 
B< 
yti' 500 600 700 
in dark 
under illumination 
»G:8 
Figure 5. Photovoltaic effect of three typical ITO-(p)S» junctions under 50mW/cm2 light intensity 
4. Conclusion 
The study showed that rectifying ITO-(p)Si heterojunction diode can be fabricated by 
thermally depositing ITO films on silicon wafer. The diodes have high series resistance 
because of the low conductivity of thermally deposited ITO layer with high defect density 
and presence of interfacial layer. These causes are thought to affect the J-V characteristics 
as well as PV effect of the junctions. The recombination of photogenerated carriers at the 
interface states, low barrier height are also responsible for low photovoltaic performance 
There are immense probabilities for improving the junction performance by controlling ana 
optimizing the deposition parameters. The works are on progress to improve the diode 
quality and PV effect by controlling the deposition parameters of the ITO layer and post 
deposition annealing for suitable conductivity and transmittivity with an interfacial layer of 
optimum thickness. 
Acknowledgment 
Two of the authors (S Chaliha and M N Borah) are grateful to University Grants Commission 
India, for awarding Teacher fellowships to carry out this research work. 
A study of current-voltage characteristics oflTO/(p) Si heterojunctions 601 
References 
H Kobayashi, T Ishida, Y Nakato and H Tsubomura J Appl Phys 69 1736 (1991) 
V Vasu and S Subrahmanyam Semicond. Sci. Technoi 7 320 (1992) 
T Mizrah and D Adler Appl. Phys. Lett. 29 682 (1976) 
j Touskova, J Kovanda, L Dobiasova, V Parizek and P Kielar Sol Energy Mater Sol Cell 37 357 
(1995) 
H L Ma, D H Zhang, P Ma, S Z Win and S Y Li Thin Solid Films 263 105 (1995) 
A Salehi Thin Solid Films 324 214 (1998) 
S Chaliha, M N Borah, P C Sarmah and A Rahman Proc of the &h Asian Thermophysical Properties 
Conference (Guwahati, India) 750 (2001) 
K L Chopra Thin Film Phenomena (New York . McGraw-Hill Company) 102 (1969) 
P C Sarmah and A Rahman Bull. Mater. Sci 21 149 (1998) 
S Chaliha, M N Borah, P C Sarmah and A Rahman Proc. of the DAE Solid State Physics Symposium 
(India) 50 395 (2005) 
E H Rhodenk Metal Semiconductor Contacts (Oxford : Clarendon Press) 87 (1978) 
E H Rhoderik Metal Semiconductor Contacts (Oxford . Clarendon Press) 7 (1978) 
S M Sze Physics of Semiconductor Devices (2nd Edn) (New Delhi * Willey Eastern Ltd) 249 (1986) 
[5 
[e: 
[7 
[8; 
[9; 
[101 
in 
113 


A Study of Current - Voltage Characteristics of ITO/(p)Si Heterojunctions

Choudhury, D K

Gogoi, Rupjyoti

Indian J Phvs. 82 (5), 621 -625 (2008) 
^tttf/ty, 
An analysis of self-similarity in quark and gluon 
densities at small x 
D K Choudhury* and Rupjyoti Gogoi 
Department of Physics Gduhati University 
Guwahati-781 014 Assam India 
E mail rupjyotigogour/ gmail com 
Abstract Sometimes back the concept of self-similarity in the structure of the proton at small x has been 
introduced We comment on the limitations of the models based on self similarity We then extend the formalism 
and phenomenology to unmtegrated and integrated gluon densities 
Keywords Self similarity hactal dimension dctp milusiu sutUfin^ Uunn dmsit) low \ 
PACS Nos 05-45 Df 47 53 +n 12 38 t 13 60 Hb 
1. Introduction 
Application of self-similarity [1,2] in hadron multiparticle production processes [3-10], 
diffractive DIS involving Pomeron exchange processes [11,12], quantum gravity [13,14] 
and quantum Regge calculus [15] are getting attention in recent years However the use 
of fractal geometry in the study of the proton structure itself has not yet attracted wider 
attention In this direction, a specific statistical quark model pursued in Ref [16] suggests 
that hadrons like proton are described by a self-similar object of fractal dimension 9/2 and 
anomalous dimension 3/2 Later in deep inelastic processes, a form of structure function 
incorporating self-similarity has been reported in Ref [17] In this approach the resultant 
expression contains four unknown parameters D0, Dv D2 and D3 to be determined from 
data While one of them is just the normalization constant, other tlree are identified as 
the fractal dimensions which are fitted to HERA collider data [18, 19] In a sense, fractality 
here is used as a tool to provide a parameterization involving a few parameters that are 
fitted to data The specific parameterization provides an excellent description of the data 
which covers a region of four momentum transfer squared 0 045 < &< 150 GeV2 and of 
Bjorken variable 6 2 x 1 0 " 7 < x < 0 2 
Corresponding Author 
© 2008 IACS 
622 D K Choudhury and Rupjyoti Gogoi 
The formalism described in Ref. [17] is based on the imposition of self-similantv 
constraints to the dimensionless unintegrated quark density qt (x,kr2) and relating them to 
the integrated density from the relation, 
q\xtf)=\dk2Tq\x,k*) 
In eq. (1) kT2 represents the transverse momentum of the quark while O2 is the four 
momentum squared of the virtual photon. One of the fitted parameter D3 was estimated to 
be negative (D3 ~ -1.2 ). Questions were therefore raised [20t21] and an alternative 
parameterization of the structure function with an estimated positive value of Dq was 
suggested recently [22]. 
Important quantities in the short distance behavior of the nucleons besides the structure 
function F/(x, Q2) are the unintegrated and integrated gluon densities xg(x,kT2) and xg(xfffi 
[23,24], It is also well known that [25-27] in the case of F2{x,GP), the gluon distribution 
enters indirectly and determines the slope in \n(CP) of the structure function. 
In the present paper, we will investigate the compatibility of gluon densities based on 
the notion of self-similarity with the approximate relations available in the literature [25-27; 
based on QCD evolution equation. We will also suggest their plausible modifications tc 
accommodate the fractal models. 
2. Formalism 
2.1. Gluon density and self-similar models : 
The forms of unintegrated and integrated gluon densities with self-similarity are identical 
to those of the quark distribution reported in Ref. [17] and [22] except the set of parameters 
will be different. Thus two alternative forms of unintegrated gluon density g(x,kf) are 
logflf'(x,fcf) = Df log)/ |og (<* + <£ 
' * 
+ C f l o g l / + £^log X ^ 3 + Dg (2) 
and 
logfl / /(x,fcf)=D?logl'x log + Dglogt x + Efiog| /0? + *rJ 
+ W 5-(3) 
Using relation similar to eq. (1), eq (2) and (3) lead to two alternative forms of gluon 
density. 
xgl(xtf) = -qf+1 -ocfntf 
1 + D^ + DflogV 
« 1 + O
2
, 
Cf+1 
"«J -1 (4) 
An analysis of self-similarity in quark and gluon densities at small x 623 
xg"(x,Oz) = >°& <$) -Gf + 1 
1-Ef-OflogV 
*»% 
I * * -
N°S'< 
<t "I (5) 
corresponding to the models of Ref. [17] and [22] respectively. 
A comparison of eqs. (4) and (5) with exact results on gluon density [27] will need 
four parameters D^ Df, D / and Df to be determined. 
But gluon densities are not directly measurable- they are measured from the slope of 
dF2/ 
the Structure function /d\0Q(f t h r o u 8 h DGLAP equations based relation |25| 
0(2**)- 9 " 3')Fl("'*] \ I 5as2 aiogO2 ' 
The relation (6) has later been improved to [26] 
v 3
 ' 5as cJlogO2 
(6) 
(7) 
In our analysis we will investigate the compatibility of relation (eqs. (6)-(7)) with self-
similarity and suggest plausible empirical modifications besides direct fitting of eq. (4) 
and (5) to exact results [27]. 
3. Results and discussion 
We choose MRST04LO[27] solutions for comparison. A comparison of eq. (4) and (5) 
with MRST04LO[27] exact results gives the following set of parameters, 
D0s= 0.339, D^= 0.073, D /= 1.5011, D3^= -1.287, O02= 0.062 for eq. (4), 
D0s= 2.5597, D^= 0.239, D2»= 1.5066 , Df = 1.435, O02= 0.049 for eq. (5), 
where we see that the values of D0 and D2 for gluons is different than that of quarks as 
obtained in Ref.[17,22]. Regarding the normalization constant D0, it may be different for 
gluons since it has a flavor dependence. Regarding D? we observe that D£>D£% which 
conforms to the feature that for any Q2, gluon is steeper than quark density. In Figure (1) 
we have plotted the variation of xg(x,&) with x for various Q2. We observe that our 
prediction lies below the exact results for C?2>50 GeV*. Regarding the formalism of 
Lastovicka, it has certain crossover point for all the Q2 values. Above the crossover point 
the result of Lastovicka lies above the exact results and below it, it lies below the exact 
results. 
624 D K Choudhury and Rupjyoti Gogoi 
Let us now discuss the compatibility of our results with the DGLAP based relations 
(6)-(7) Our preliminary investigation shows that indeed the gluon is related to the slope of 
the structure function but the relation between them don't obey (6)-(7). They are slightly 
modified Empirically we have found, eqs. (6) and (7) are modified to 
a(2**)..*2i5££) 
1
 ' 5as2 aiogO2 
f(x) 
with f(x) = x01404 and f(x) = x°A74B corresponding to eq. (4) and (5) respectively. 
A similar modification of eq. (7) is, 
1/3' ' 5« s OlogO2 H ) 
with f(x) = x°457 and f(x) = x°G43A corresponding to eqs. (4) and (5) respectively 
(8) 
(9) 
x 
60 -
5 0 -
40 -
T0 -
iQ-
10-
0 -
6 0 -
5 0 -
1 
4 0 -
1 0 -
2 0 -
1 0 -
0 -
,
 1 
• 
• 
I 
• 
* 
1 
0'=25GeV? 
• MHST04LO 
this work 
Re» (17) 
4 ^ 
* 
"^ 
• • • • • • * • ! 1 
• MRST04LO 
this work 
Ref (17) 
k. 
\ 
% 
« 
I ' « I 
Q =30GeV* 
v • MRST0410 
this work ' 
• RBI (17) 
• \ 
» 
* 
m 
• • 
Q'-50GoV } 
J • MRST04LO 
,_ this work 
Rel (17) 
^ 
\ \ ' 
-• 
| I 
Q'= J5GeV 
• MRST0410 
1
 this work 
* Ref (17) 
• 
• 
B 
• 
' • • ' ' " • • ! i—i t i im| •—i 11 I I I I | 
Q?»55GeV 
• MRST04LO 
• Jhib work 
N* R<* (W) 
\ \ 
V X 
* 
•
 m 
• 
— \ — . - • \ — 
• 
• 
d 
•, 
\ 
• 
• 
• 
\ » 
0 =40GoV 
• MRST0410 
this work 
Ref (17) 
\ 
a 
•m 
0 /*65GeV'' 
• MRST04LO 
this work 
Rot (17) 
v 
N 
• 
" * . 
-+**\ M 
Figure 1. xg(x,CP) as a function of x in bins of & 
An analysis of self-similarity in quark and gluon densities at small x 625 
Acknowledgment 
One of the authors (Rupjyoti Gogoi) is thankful to Council of Scientific & Industnal Research, 
New Delhi for financial support. 
References 
[1] B B Mandelbrot Fractal Geometry of Nature ( N Y W H Freeman) 1983) 
[2] Michael FBarnsley Fractal Everywhere (NY • Academic Press) (1993) 
[3] P Carruthers and Minh Duong-Van Los Alamos Report No LA-UR-83-2419 (unpublished) 
[4] I M Dremin Mod Phys Lett A3 1333 (1988) 
[5] R Lipa and B Buschbeck Phys lett B223 465 (1989) 
[6] R C Hwa Phys Rev D41 1456 (1990) 
[7] WFIokowski and R C Hwa Phys Rev D43 1548 (1991) 
[81 W Yuanfug and L Lianshbu Int J Mod Phys A53 37 (2003) 
[9] D K Ghosh et al, Fizika 12 227 (2003) 
(10] D K Ghosh et al, Fractals 13 325 (2005) 
[11] Y Zhang hep-ph/9802269 
[12] Y Zhang in Proceedings of the XXVII International Symposium on Multiparticle dynamics Delphi, 
Greece, Ed N G Antoniou et al (Singapore World Scientific) p 271 (2000) 
[13] J Ambjorn et al Nucl Phys B454 3133 (1995) hep-ph/9507014 
[14] M Bowick et al Phys Lett B403 197 (1997) hep-ex/9608030 
[15] J Nishimura and M Oshikawa Phys Lett 338 187 (1994) 
[16] S N Banerjee, A Bhattacharya, B Chakraborty and S Banerjee Int J Mod Phys A15 2053 (2000), 
ibid A16 4939 (2001), ibid A17 4939 (2002) 
[17] T Lastovicka Euro Phys J C24 529(2002), hep-ph/0203260, PhD Thesis DESY Thesis 2004-010 
(Berlin Humboldt University) (2003) 
[18] H1 C Adloff et al, Euro Phys J C22 33 (2002), hep-ex/0012053 
[19] ZEUS J Bnetweg et al, Phys Lett B487 53 (2000); hep-ex/0005018 
[20] D K Choudhury and Rupjyoti Gogoi hep-ph/0310267 
[21] D K Choudhury and Rupjyoti Gogoi hep-ph/0503047; Indian J Phys 80(6) 659 (2006) 
[22] D K Choudhury and Rupjyoti Gogoi Indian J Phys 80(8) 823 (2006) 
[23] G Gustafson hep-ph/0312313 
[24] H Jung, A V Kotikov, A V Lipatov and N P Zotor, hep-ph/0611093 
[25] K Prytz Phys. Lett. B311 286 (1993) 
[26] K Bora and D K Choudhury Phys Lett B354 152 (1995) 
[27] MRST A D Martin, R G Roberts, W J Stirling and R S Thorne Euro Phys J C14 133 (2000), hep-
ph/9907231, Phys Lett B531 216 (2002) 


An Analysis of Self-Similarity in Quark and Gluon Densities at Small X

Deb, S

Sarkar, D

Indian J Pins 82 (6), 715-718 (2008) 
3
 MM 
Fabrication of silver/cross-linked polyvinyl alcohol 
nanoparticles by hydrothermal method 
S Deb and D Sarkar1 
Department of Phvsics Gduhati Univeisitv Guwdhdti 7S1 OH Assam Indwi 
L mail sarkardeepalif" rediffmail com 
Abstract In this article, we report the fabrication of nanometer sized silver partic les by simple hydrothermal 
method Obtained nanoparticles are nearly spherical and have a narrow size distribution (20 30nm) as found in 
SEM pictures The very strong plasmon resonance peak at 423 441 nm ranges in UV-Visible spectra is a 
consequence of the nano sized Ag particles XRD patterns show a characteristic peak for silver nanoparticles 
at 20 - 40° FTIR spectra reveals the evidence of silver PVA cross-linking The I V curve exhibits non ohmic 
behaviour with maximum current 5 9 /J A at 20 V 
K e y w o r d s Silvc? nunopuititks polymu composite h\chtithc iITIJI pi ismon usonanti pt.ik 
PACS Nos. 61 46 Df 81 16 Be 81 40 Tv 
1. Introduction 
The materials with nanometer grain sizes in one (nanowire), two (nanoflakes, nanoscales 
etc) or three dimensions (nanosphere, nanorod, etc) have the unique physical, chemical, 
and mechanical properties that are neither those of bulk materials nor those of molecular 
compounds. These have been exploited for the extensive potential applications in optics, 
electronics, magnetic, catalysis, chemical sensing, biomedicine, micro-reactor etc Noble 
metal nanoparticles/ organic polymer films are of particular interest because of their potential 
application for photonics and electro-optics [1-4] The polymers prevent oxidation and 
coalescence of the particles and provide them long time stability As a result, the optical 
and electrical properties of the nanoparticles can be brought into full play, while the typical 
advantages of organic polymers (eg. elasticity, transparency, relatively simple way of 
synthesis etc) are retained in the composite films Several methods have been developed 
for the fabrication of nanocomposite films containing noble metal nanoparticles dispersed 
in polymer matrix. 
Corresponding Author 
©2008 I ACS 
716 S Deb and D Sarkar 
We report in this work the hydrothermal synthesis of silver nanoparticles in aqueous 
solution using polyvinyl alcohol (PVA) (which is very commonly available inexpensive 
polymer) as both reducing and stabilizing agent (i.e. without the use of an additional 
reducing agent). The characterization of synthesized Ag/ PVA nanofilms is done by SEM. 
XRD, and UV-Vis spectrometry. Also the electrical property of the composite films is 
studied through l-V characteristics in order to explore more in the direction of applicability 
in electro- optic devices. 
2. Experimental details 
Silver nanoparticles are prepared by reducing silver nitrate (AgN03) of different concentrations 
in PVA solutions. In 3wt% PVA solution silver nitrate is added drop wise with a continuous 
stirring. The temperature of the solution is kept at 90° c. The change of colour of the 
resultant solution from colourless to yellow after about 2hrs. indicates the nano formation 
The resultant solution is spin cast on various substrates for further investigation. 
3. Result and discussion 
3.1. UV-Vis spectroscopy: 
The presence of a very strong plasmon resonance peak at 423nm- 441 nm range in the 
UV-visible spectra for different concentrations of AgN03 is a clear consequence of formation 
of nano sized silver particles. Figure 1 shows UV-Vis absorption spectra of spin cast 
films. This shows characteristics plasmon band of silver nano as has been found in silver 
nano fabricated in polysodium acrylate matrix [5] (which is much costlier and not so 
readily available). 
3 
CO 
u 
c 
03 
J3 
w. 
O (ft 
< 
1 a 
1 & 
14 
1.2 
i 
OB 
06 
04 
0.2 
0 
300 400 500 600 700 800 
Wavelength (nm) 
Figure 1. Absorbance for 1mM AgN03. 
3.2. SEM Image: 
Figure 2 shows SEM image of PVA/Ag nano film. SEM image shows the average size of 
the grains in the range 20-30nm. 
Fabrication ofsilver /cross-linked polyvinyl alcohol nanopariicles etc
 7 1 7 
33 XRD Pattern-
The XRD pattern is taken by Seifert XRD 3000pd d.ffractometer with cu-ku (0 15418nm) 
Figure 3 shows XRD pattern of PVA/Ag nano films This shows characteristic peak of 
silver (fee) nano at 20 = 40° for (111) plane as have been seen ,n silver nano synthesized 
in polyvinyl pyrrolidone matrix by polyol process [6] (which involves many stages of chemical 
preparations) 
u 1250 
Figure 2. SEM image PVA/Ag nano film 
3 4 FTIR spectra 
Figure 3 XRD pattern of Ag nano 
FTIR spectra of the spin cast films show a clear shift in band from that of pure PVA, 
which indicates the PVA-silver, cross-linking Figure 4 shows the FTIR spectra of PVA/ 
silver nano film. 
I 
* I 
I 
,* 
/ f 
! ./ 
' i *** h 
k <&* -
\ l 
J i 
4000 3500 3000 2500 2000 1500 
Wave number / cm"1 
Figure 4. FTIR spectra of (a) PVA and (b) PVA/Ag nano 
1000 500 
718 S Deb and D Sarkar 
3.5. I-V characteristics: 
The electrical properties of PVA/Ag nanoparticles are measured by l-V curves taken by 
Keithley CV meter (model 595). I-V curves show similar non-ohmic behaviour both in-
plane as well as perpendicular electrode configurations. For in- plane configuration, on the 
top of the film two small areas are coated with silver paint and connections are taken by 
fine copper wires. For perpendicular configuration, the film is spin cast on ITO glass and 
top electrode is taken as earlier Figure 5 shows LOG I- LOGV curve with maximum 
current 5900 nA for 20 Volts. 
Conductivity of imM Ag Nano 
LOG V (Volts) 
Figure 5. I-V characteristic of PVA/Ag nano 
4. Conclusion 
In summery, silver nano spheres are successfully synthesized by hydrothermal method in 
PVA polymer, which acts as both reducing and stabilizing (the polymer prevent oxidation 
and coalescence of the particles and provide them long time stability) agent. This method 
of nanocomposite preparation offer advantages of: (1) A cluster or atomic level control and 
(2) an efficient scale up for processing and production. We hope to have structure- property 
correlation and nano device application in future. 
References 
[1] P Buffat and J P Borel Phys. Rev. A13 2287 (1976) 
[2] M Wautlet Nanotechnology 3 42 (1992) 
[3] G Schmidt Chem. Rev. 92 1709 (1992) 
[4] L N Lewis Chem. Rev. 93 2693 (1993) 
[5] I Hussain, M Brust, A J Papworth and A I Cooper Langmuir 19 4831 (2003) 
[6] G Carotenuto, G P Pepe and L Nicolias Eur. Phys. J. B16 11 (2000) 


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Foreword

Notes for Contributors

Front Contents

Performance of Thermally Deposited Polycrystalline Ge-Thin Film Transistors with a Copper Interlayer Fabricated on Glass Substrates

A Study of Current - Voltage Characteristics of ITO/(p)Si Heterojunctions

An Analysis of Self-Similarity in Quark and Gluon Densities at Small X

Fabrication of Silver/Cross-Linked Polyvinyl Alcohol Nanoparticles by Hydrothermal Method

Advisory Board and Editors

A Forgotten Variational Principle

A Model for Quark-Gluon Plasma with Pentaquark Baryons and Tetraquark Mesons

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