97,319 research outputs found
Small channel-length SiC nanowire field-effect transistors
No full textNM03.10.12 Small Channel-Length SiC Nanowire Field-Effect Transistors Ali Uzun and Kasif Teker; Electrical and Electronics Engineering, Istanbul SehirUniversity, Istanbul, Turkey.Low-dimensional semiconductor materials offer new ways to develop nanoscaleelectronic and optoelectronic devices and components. From the class of wide band gap semiconductor nanomaterials, SiC nanowires combine the uniqueproperties of one-dimensional materials with that of superior intrinsic SiC characteristics and offer great opportunities for high power and high frequencyelectronic devices as well as in sensors capable of operating at high temperatures or hostile environments.This study presents a systematic investigation of electronic transport properties of p-type SiC nanowire field effect transistors (SiCNW-FET) with multiplechannel lengths (smallest channel length SiCNW-FET reported). The investigation has focused on the parameters including transconductance (gm), carriermobility (µh), ON-OFF current ratio (gating effect- Ion/Ioff). Further, a comprehensive comparison of our experimental measurements with the previouslyreported theoretical and experimental studies is presented.MOCVD-grown long SiCNWs with diameters about 60 nm are placed on a highly doped SiO2/Si substrate. The electrodes (Cr/Au: 3nm/100nm) aredefined by the e-beam lithography (EBL) with varying channel lengths of 120 nm, 220 nm and 1.5 µm followed by metal deposition through e-beamevaporation. The initial electrical measurements from the fabricated p-type SiCNW-FETs exhibited transconductance of 6.9x10-9 A/V (@ Vds = 0.05V),carrier mobility of 1.7 cm2/V.s, carrier concentration (nh) of 3.72 x 1020 cm-3, and Ion/Ioff ratio more than 104 for a device with 120nm channel length. Thegating effect achieved in this study is the highest value reported in the literature for a SiCNW-FET, to the best of our knowledge. As a consequence, thisstudy shows the great potential of SiCNW-FETs to be utilized in nanoelectronic and nanophotonic applications
Enhanced photoresponse of a self-powered gallium nitride photodetector via sequentially-deposited gold nanoparticles for sustainable optoelectronics
No full text© 2023, The Minerals, Metals & Materials Society.It is becoming crucial to design/fabricate eco-friendly, sustainable electronic and photonic devices to minimize the carbon footprint for future systems. In this study, we have demonstrated a steady photoresponse enhancement of the self-powered GaN ultraviolet photodetector (GaN-UVPD) via sequentially deposited gold nanoparticles (Au NPs) under 254, 302, and 365 nm UV light exposure. The AuNP-deposited GaN-UVPD exhibited excellent responsivity of 0.65 A/W and detectivity of 6.51 × 1012 cm.Hz1/2 W−1 under 302 nm UV light without any external power. Moreover, the sensitivity of the device increased from 1.98 × 106% to 3.32 × 106% following Au nanoparticle deposition. Additionally, the plausible mechanisms for the self-powered and Au nanoparticle-induced photoresponse enhancement have been discussed. In brief, the high-performance photoresponsivity of our self-powered GaN-UVPD could find many useful applications in sustainable energy and eco-friendly optoelectronic devices
Removal of Rhodium (III) from Aqueous Solution by Na- and K-Treated Clinoptilolites
No full textThe clinoptilolite which was modified with sodium and potassium chloride was found to have adsorption capacity for rhodium. To evaluate the adsorption capacity and characteristics, the effects of solution pH, dose of clinoptilolite loading, contact time, temperature, and initial rhodium concentration were investigated in a batch mode. Adsorption was decreased with the increasing temperature for both modified clinoptilolites. The Langmuir and Freundlich adsorption models were used for mathematical description of the adsorption equilibrium. Equilibrium data were fitted to the Langmuir model in the concentrations of 2-60 mg l(-1) at 293 and 313 K. Based on the Langmuir isotherm plots, the maximum adsorption capacity value was calculated to be 0.415 mg g(-1) at 293 K. Various thermodynamic parameters such as a dagger GA degrees, a dagger HA degrees, and a dagger SA degrees were evaluated with results indicating that this system was an exothermic spontaneous reaction and kinetically suited to the pseudo-second-order model
Low-power operating aluminum nitride nanowire-film ultraviolet photodetector
No full text© 2022 Trans Tech Publications Ltd, Switzerland.This work presents the fabrication and testing of a cost-effective, low power consuming, high sensitivity aluminum nitride nanowire-film-based ultraviolet photodetector. Time-dependent dynamics of photocurrent rise and decay have been investigated with varying applied bias ranging from 1 V to 20 V by periodical exposures to 254 nm ultraviolet light. The device shows stable and repeatable photocurrent cycles at a low bias voltage of 1 V indicating the sensitivity and low power operating capability. Furthermore, the photocurrent increases as the bias voltage increases such that the photocurrent at 20 V is approximately seventeen times larger than that of at 1 V. Despite the relatively long device channel length, the device reveals a quick response with a rise time of 270 ms. Moreover, the responsivity of the photodetector has been determined as 3.78 mA/W and 0.201 mA/W at 20 V and 1 V, respectively. This study demonstrates the potential of aluminum nitride nanowires for applications in next generation, low power consumption nanoscale optoelectronic devices in advanced communication, flame detection, air purification, ozone sensing, leak detection and other space monitoring
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Gallium nitride nanowire field effect transistor for high temperature applications
No full textF.SF01.09.04 Gallium Nitride Nanowire Field Effect Transistor for High Temperature Applications Abstract Body: Wide bandgap (WBG) semiconductor-based electronics are becomingthe center of interest due to their ability to operate at high temperatures and highvoltages. Gallium Nitride (GaN), as one of the WBG semiconductors, is a strongcandidate that can meet expectations in high-temperature electronic applications suchas military systems, automotive and aerospace control units, gas and oil explorationdrilling systems. The superior physical properties of GaN nanowires such as high directbandgap, high breakdown voltage, and high thermal conductivity, as well as highsurface area to volume ratio, make it even more signiÒcant material for harshenvironments. In this work, we investigate the electrical transport properties of a backgated single GaN nanowire Òeld-e×ect transistor (GaNNW-FET) at elevatedtemperatures. In order to analyze transport properties (IDS-VDS and IDS-VGS),electrical measurements were performed at temperatures ranging from roomtemperature to as high as 350°C. The device performs very well until 250°C, whereas itshows some reduction in current values beyond 300°C. In fact, the drain currentincreases by 2.1, 13.6 and 19.7 times at the temperatures of 100°C and 200°C, 250°C,respectively, with respect to room temperature current at the same bias voltage of 1 V.The enhancement of current is likely due to the reduction of contact resistancebetween the nanowire and electrodes as well as an increase in thermally excited carrierconcentration. On the other hand, degradation of current is likely due to the increase inlattice scattering, lowering the carrier mobility, of the GaN nanowire. Moreover, theinÓuence of high temperature on important transport properties such astransconductance, carrier concentration and carrier mobility will be presented indetails. The device o×ers the following unique advantages: (i) stable operation at hightemperatures (at 350°C), (ii) exhibiting an on/o× current ratio of 5.5 x 102 and a hightransconductance value of 3.09 µS at 350°C indicating a good gating e×ect even at hightemperatures, and iii) o×ering solutions not only for high-power but also for low-powercircuit and photonic applications at high temperature ambients (> 300oC). In summary,GaNNW-FET proves to be an excellent device capable of operating at hightemperatures enabling the development of high-performance nanoelectronic/photonicdevices especially for harsh conditions
Fabrication of a fine-pattern flexible nanowire photodetector by shadow mask
No full textF.NM01.10.09 Late News: Fabrication of a Fine-Pattern Flexible Nanowire Photodetector by Shadow Mask Abstract Body: Recently, ultraviolet photodetectors (UVPDs) have been used on largescale applications such as environmental monitoring, flame detection, spacecommunication, biomedical applications, pharmaceutical, and chemical analysis.Besides, advances in internet technologies such as the internet of things (IoT) endorsethe integration of sensors more rapidly in every aspect of our lives. This trend demandsthe fabrication of smaller, lighter, less complicated, and low power devices. Therefore,designing low cost, self-powered, highly sensitive, Óexible UVPD nanodevices arebecoming a hot research area for near future optoelectronics. Silicon carbide (SiC), awide bandgap semiconductor, is an excellent contender to fulfill those expectations. Inaddition to having characteristics of one-dimensional nanostructure such as highsurface to volume ratio, high crystalline quality, SiC nanowires also possess superiormaterial attributes like high breakdown voltage, high thermal conductivity, high driftvelocity, excellent chemical and physical stability. In this study, we propose a very cost-effective, flexible, self-powered single SiC nanowire ultraviolet photodetector (SiCNWUVPD) fabricated on a polyvinylchloride (PVC) substrate. The self-powered flexibleSiCNW-UVPD was fabricated via a commercially available transmission electronmicroscopy (TEM) grid (physical mask) and a sputter coater system. Gold (Au)electrodes of 110 µm x 110 µm and a gap of 4 µm were successfully achieved withoutthe use of complicated and expensive methods like photolithography. Two-probephotocurrent-time (I-t) and I-V measurements were performed to revealphotoresponse characteristics such as the photo-to-dark current ratio (PDCR),sensitivity, and responsivity under 254 nm wavelength UV light at 0 V bias. A shallowdark current around 0.087 pA and a good PDCR value of 18 are obtained. Moreover,sensitivity and responsivity values are calculated as 1756 and 170 mA/W, respectively.In addition, the specific detectivity calculations, the e×ect of bias, and vigorous bendingtest results are discussed as well. Our work provides the following unique advantages:(i) to the best of our knowledge, the first demonstration of a single SiC nanowire PD ona flexible substrate with great performance, (ii) a very cost-e×ective fabrication methodand readily applicable to any substrate, (iii) exhibiting high sensitivity and responsivityvalues under UV light at 0 V bias. Therefore, our SiCNW-UVPD device presents anopportunity for low-cost, easy to fabricate, self-powered photodetectors for upcomingfuture technologies such as wearable sensors, electronic skins, and the internet ofthings
RECOVERY OF SILVER FROM AQUEOUS SOLUTION BY WATER HYACINTH (EICHHORNIA CRASSIPES) ROOTS
No full textRoots of water hyacinth, Eichhornia crassipes, were found to have biosorption capacity for silver. To evaluate the biosorption capacity and characteristics, the effect of solution pH, dose of biosorbent loading, contact time, temperature and initial silver concentration were investigated in a batch mode. The Langmuir and Freundlich adsorption models were used for mathematical description of the sorption equilibrium. Equilibrium data was fitted to the Langmuir model at 293 and 398 K and concentrations of 10-150 mg L-1. Based on the Langmuir isotherm plots, the maximum biosorption capacity value was calculated to be 141.54 mmol g(-1) at 293 K. Various thermodynamic parameters, such as Delta G degrees, Delta H degrees, and Delta S degrees, were evaluated with results indicating that this system was an exothermic spontaneous reaction and kinetically suited to pseudo second order model
Direct Transfer Manufacturing of Flexible Silicon Carbide Nanowire-Network Prototype Device
No full textFlexible and transparent devices are expected to meet increasing consumer demands for upgrades in wearable devices, smart electronic and photonic applications. In this work, nanomanufacturing of a flexible and powerless silicon carbide nanowire network ultraviolet photodetector (SiCNW-network UVPD) prototype was investigated by a very cost-effective direct transfer method. Indeed, the powerless device exhibited a photo-to-dark current ratio (PDCR) of 15 with a responsivity of 5.92 mA/W at 254 nm wavelength exposure. The reliability and durability of the device was evaluated by bending tests. In fact, the PDCR of the device was still very good even after seventy-five bending cycles (similar to 96 % of the rest state). In brief, our flexible, powerless SiCNW-network UVPD device with cost-effectiveness, good performance, and durability can provide feasible alternatives for new generation wearable optoelectronic products
3C-SiC/Si heterostructure for self-powered multiband (UV-VIS) photodetection applications
No full textThis study reports a self-powered 3C-SiC/Si heterostructure photodetector in both metal-semiconductor-metal (MSM) and heterojunction (HET) configurations and capable of operating under ultraviolet and visible light (UV-vis). The single crystalline 3C-SiC thin film was grown epitaxially on a Si (111) substrate by employing a two-step growth process. MSM configuration exhibited a peak responsivity of 0.334 A W-1 and a specific detectivity of 5.4 x 10(11) cm.Hz(1/2).W-1 (Jones) under white light illumination. However, in the UV region, photocurrent showed an increasing behavior with a decrease in the UV wavelength from 365 nm to 254 nm. The peak responsivity and specific detectivity values of the HET configuration were also determined under white light illumination with 0.167 A W-1 and 4.4 x 10(11) Jones, respectively. Furthermore, both devices exhibited very fast rise and decay times as 3.8 ms and 3.6 ms for the MSM, and 6 ms and 8 ms for the HET configuration (fastest reported on 3C-SiC). In brief, our self-powered 3C-SiC/Si heterostructure with multiband (UV-vis) photodetection sensitivity and fast speed could offer new solutions for the eco-friendly and sustainable optoelectronic applications
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