1,720,984 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
Aluminium nitride nanowire array films for nanomanufacturing applications
No full textThe present paper presents a systematic investigation of both catalyst free and catalyst assisted AlN nanowire synthesis by chemical vapour deposition using Al and NH3 as source materials. Growth runs have mostly been carried out at 1100°C under H2 as carrier gas. While the catalyst free growth runs resulted in long (∼40 μm) and dense AlN nanowire array films, the catalyst assisted growth resulted in short nanowires (3-5 μm). Growth mechanisms have been presented. Raman spectroscopy of the catalyst free grown nanowires has revealed very symmetric and strong phonon modes [e.g. strong E2 (high)] indicating very good crystal quality of the grown AlN nanowires. In brief, catalyst free growth eliminates catalyst contamination and produces high quality and density of long nanowires, which is very valuable for scale-up manufacturing opportunities of the AlN nanostructures
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
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
Effect of pH on transport characteristics of silicon carbide nanowire field-effect transistor (SiCNW-FET)
No full textThis paper investigates the effect of pH on transport properties of silicon carbide nanowire field-effect transistor (SiCNW-FET) including the key parameters such as transconductance, resistivity, stability, and repeatability of the device towards harsh environment-sensing applications. Transport properties were investigated under different pH solutions ranging from pH 5 to pH 9. The device exhibited a high transconductance of 4.5 mS and a very low resistivity of 0.065 m omega cm at pH 5 at a bias voltage of 2 V. The device showed an increase in conductance (from 2.66 to 4.5 mS) after applying the solution with pH 5 and then a substantial decrease in conductance (from 4.5 to 0.15 mS) with increasing the pH from 5 to 9 was observed. The changes in conductance can be attributed to the metal oxide/electrolyte binding sites model and to the hydrogen ions adsorption on the surface of the SiC nanowires altering the total surface charge density. The device exhibited almost a full recovery after rinsing with DI water, achieving good stability and repeatability. In consequence, this study would contribute to the development of low-power and cost-effective 3C-SiCNW-based FETs for use in the fields of bio- and environmental sensing, as well as biomedical applications
Density and morphology adjustments of gallium nitride nanowires
No full textThis paper presents the morphology and density adjustments of GaN nanostructures via CVD process. GaN nanostructure growth has been carried out using Ga and NH3 as source materials with various catalyst materials, such as Au, Ni, Ag, and Fe between 800 and 1100 °C. The investigation has focused on the effects of process parameters, such as growth temperature and catalyst materials on the GaN nanowire morphology and density. Low temperature (<950 °C) growth runs resulted in microscale-faceted crystals and short nanorods regardless of the catalyst type or reactor pressure. Conversely, high temperature (1100 °C) growth runs resulted in ultra-dense interwoven long nanowires with multi-prong growth mechanism. A detailed analysis for the transition from microscale-faceted crystals to ultra-dense multi-prong-grown GaN nanowires is provided. Furthermore, electrical characteristics of the grown nanowires have been demonstrated through a very efficient fabrication scheme. Consequently, multi-prong growth mechanism reduces catalyst contamination and produces high density of long nanowires, which is very crucial for scale-up manufacturing opportunities
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
Low-power operating aluminum nitride nanowire-film ultraviolet photodetector
Full text link© 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
Investigation of ph effect on the performance of undoped silicon carbide nanowire field-effect transistors for the development of chemical sensors and biosensors
No full textThe effect of pH on the performance of undoped silicon carbide nanowire field-effect transistors (SiCNW-FETs) was systematically studied using various solutions with pH ranging from pH 2 to pH 13 and important transport parameters such as transconductance, mobility, and resistivity were reported. Interestingly, at 2 V, alkaline solutions with high pH value (pH 13) revealed a higher transconductance of 7.13 nS and lower resistivity of 40 omega cm as compared to acidic solutions with 0.01 nS and 2.1x10(4) omega cm at pH 2, respectively. A model describing the pH-dependent conductance of the SiCNW-FETs was proposed. Moreover, a comprehensive comparison of the pH effects on the transport properties of the undoped SiCNW-FETs and nitrogen-doped SiCNW-FET was presented and the measurements clearly revealed opposite trends for a wide range of pH solutions. In short, our SiCNW-FETs with high sensitivity, high stability, and minuscule sample volume can provide solutions for the development of harsh environment compatible nanosensors for chemical, biochemical, and environmental sensing applications
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