scholarly journals Unveiling the detection dynamics of semiconductor nanowire photodetectors by terahertz near-field nanoscopy

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Eva A. A. Pogna ◽  
Mahdi Asgari ◽  
Valentina Zannier ◽  
Lucia Sorba ◽  
Leonardo Viti ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Near Field ◽  
Low Noise ◽  
Optical Measurements ◽  
Photon Density ◽  
Electric Response ◽  
Clear Understanding ◽  
Strong Nonlinearity ◽  
Semiconductor Nanowire ◽  
Photo Response

AbstractSemiconductor nanowire field-effect transistors represent a promising platform for the development of room-temperature (RT) terahertz (THz) frequency light detectors due to the strong nonlinearity of their transfer characteristics and their remarkable combination of low noise-equivalent powers (<1 nW Hz−1/2) and high responsivities (>100 V/W). Nano-engineering an NW photodetector combining high sensitivity with high speed (sub-ns) in the THz regime at RT is highly desirable for many frontier applications in quantum optics and nanophotonics, but this requires a clear understanding of the origin of the photo-response. Conventional electrical and optical measurements, however, cannot unambiguously determine the dominant detection mechanism due to inherent device asymmetry that allows different processes to be simultaneously activated. Here, we innovatively capture snapshots of the photo-response of individual InAs nanowires via high spatial resolution (35 nm) THz photocurrent nanoscopy. By coupling a THz quantum cascade laser to scattering-type scanning near-field optical microscopy (s-SNOM) and monitoring both electrical and optical readouts, we simultaneously measure transport and scattering properties. The spatially resolved electric response provides unambiguous signatures of photo-thermoelectric and bolometric currents whose interplay is discussed as a function of photon density and material doping, therefore providing a route to engineer photo-responses by design.

scholarly journals Nanonet: Low-temperature-processed tellurium nanowire network for scalable p-type field-effect transistors and a highly sensitive phototransistor array

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Muhammad Naqi ◽  
Kyung Hwan Choi ◽  
Hocheon Yoo ◽  
Sudong Chae ◽  
Bum Jun Kim ◽  
...  
Keyword(s):  
Low Temperature ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistors ◽  
Optical Measurements ◽  
Electrical Performance ◽  
Large Area ◽  
Nanowire Network ◽  
P Type ◽  
Nanowire Networks

AbstractLow-temperature-processed semiconductors are an emerging need for next-generation scalable electronics, and these semiconductors need to feature large-area fabrication, solution processability, high electrical performance, and wide spectral optical absorption properties. Although various strategies of low-temperature-processed n-type semiconductors have been achieved, the development of high-performance p-type semiconductors at low temperature is still limited. Here, we report a unique low-temperature-processed method to synthesize tellurium nanowire networks (Te-nanonets) over a scalable area for the fabrication of high-performance large-area p-type field-effect transistors (FETs) with uniform and stable electrical and optical properties. Maximum mobility of 4.7 cm2/Vs, an on/off current ratio of 1 × 104, and a maximum transconductance of 2.18 µS are achieved. To further demonstrate the applicability of the proposed semiconductor, the electrical performance of a Te-nanonet-based transistor array of 42 devices is also measured, revealing stable and uniform results. Finally, to broaden the applicability of p-type Te-nanonet-based FETs, optical measurements are demonstrated over a wide spectral range, revealing an exceptionally uniform optical performance.

Low Noise Junction Field Effect Transistors in a Silicon Radiation Detector Technology

2006 ◽  
Vol 53 (5) ◽  
pp. 3004-3012 ◽  
Author(s):  
G.-F. Dalla Betta ◽  
M. Boscardin ◽  
F. Fenotti ◽  
L. Pancheri ◽  
C. Piemonte ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Radiation Detector ◽  
Low Noise ◽  
Detector Technology ◽  
Junction Field Effect Transistors

Direct-Write Complementary Graphene Field Effect Transistors and Junctions via Near-Field Electrospinning

Small ◽  
2014 ◽  
Vol 10 (10) ◽  
pp. 1920-1925 ◽  
Author(s):  
Jiyoung Chang ◽  
Yumeng Liu ◽  
Kwang Heo ◽  
Byung Yang Lee ◽  
Seung-Wuk Lee ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Near Field ◽  
Direct Write

Sub-micron Optoelectronic Properties of Polycrystalline Solar Cell Materials

2005 ◽  
Vol 865 ◽  
Author(s):  
S. Smith ◽  
R. Dhere ◽  
T. Gessert ◽  
P. Stradins ◽  
T. Wang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Grain Boundaries ◽  
Surface Passivation ◽  
Near Field ◽  
Spectroscopic Properties ◽  
Optoelectronic Properties ◽  
Cdte Solar Cells ◽  
Cell Structures ◽  
Photo Response

AbstractGeneration, transport and collection of carriers in polycrystalline (PX) solar cells and their constituent materials are poorly understood, and significantly different than in their single-crystal counterparts. Recent theoretical and experimental results have put forth the expectation that grain boundaries in PX-solar cell materials such as CdTe and CuInGaSe2, either as-grown or after appropriate post-growth treatment, may have electronic properties which are advantageous to charge separation and solar cell operation[1-3]. However, a microscopic picture of the spatial variations in the optoelectronic properties of these materials is, for the most part, still lacking. The goal of the work reported here is to explore the optoelectronic and spectroscopic properties of grain-boundaries in these materials at the nanometer length-scale, via novel, high-resolution optical techniques. Towards this end, a significant enhancement in photo-response near grain boundaries in CdTe solar cells, consistent with models put forth in reference 2, was observed via near-field Optical Beam Induced Current (n-OBIC) [4]. A systematic μ-PL study of the effect of CdC12-treatment on recombination in CdTe/CdS solar cell structures of varying thickness directly examined the variation in optoelectronic properties at grain-boundaries in this material, revealing the grain-boundary and surface passivation effects of this important post-growth processing step. For comparison, we also studied the effects of SiNx post-growth treatment and annealing on the photo-response of PX-silicon solar cells using n-OBIC. These results and our most-recent n-OBIC measurements in CdTe and CuInGaSe2 solar cells are discussed.

RECENT PROGRESS ON GaN-BASED ELECTRON DEVICES

2006 ◽  
Vol 16 (02) ◽  
pp. 469-477
Author(s):  
Yasuhiro Uemoto ◽  
Yutaka Hirose ◽  
Tomohiro Murata ◽  
Hidetoshi Ishida ◽  
Masahiro Hikita ◽  
...  
Keyword(s):  
Noise Figure ◽  
Field Effect Transistors ◽  
Drain Current ◽  
Low Noise ◽  
60 Ghz ◽  
Si Doping ◽  
Power Handling Capability ◽  
Source Resistance ◽  
State Breakdown ◽  
A Current

We present results of some novel AlGaN/GaN heterojunction field-effect transistors (HFETs) specifically developed for RF front-end and power applications. To reduce the parasitic resistance, two unique techniques: selective Si doping into contact area and a superlattice (SL) cap structure, are developed. With the selective Si doping method, a transistor with an on-state resistance as low as 1.86 Ω·mm and a Tx/Rx switch IC with very low insertion loss (0.26 dB) and very high power handling capability (P1dB over 40 dBm) were obtained. With the SL cap HFETs, an ultra low source resistance of 0.4 Ω·mm was achieved and excellent DC and RF performances were demonstrated. The typical characteristics of these HFETs are: maximum transconductance of over 400 mS/mm, maximum drain current of 1.2 A/mm, cut-off frequency of 60 GHz, maximum oscillation frequency of 140 GHz, and a very low noise figure of 0.7 dB with 15 dB gain at 12 GHz. For power applications, in order to significantly reduce fabrication cost, we fabricated the AlGaN/GaN HFET on a conductive Si substrate with a source-via grounding (SVG) structure. The device has a very low on-state sheet resistance of 1.9 mΩ·cm2, a high off-state breakdown voltage of 350 V, and a current handling capability of 150 A. In addition, a sub-nano second switching response with t r of 98 ps and t f of 96 ps with a current density as high as 2.0 kA/cm2 is demonstrated for the first time.

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