scholarly journals GaN Schottky Diode with TiW Electrodes on Silicon Substrate Based on AlN/AlGaN Buffer Layer

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Sheng-Po Chang
Keyword(s):  
Buffer Layer ◽  
Quantum Efficiency ◽  
Schottky Diode ◽  
Silicon Substrate ◽  
Dark Current ◽  
Noise Equivalent Power ◽  
Incident Wavelength ◽  
Sapphire Substrates ◽  
Contact Electrodes ◽  
Algan Buffer

We report the fabrication of GaN Schottky photodiodes (PDs) on Si(111) substrates coated with an AlN/AlGaN buffer multilayer. It was found that their dark current was much smaller than that of identical devices prepared on sapphire substrates. With an incident wavelength of 359 nm, the maximum responsivity of the n−-GaN Schottky photodetectors with TiW contact electrodes was 0.1544 A/W, corresponding to a quantum efficiency of 53.4%. For a given bandwidth of 1 kHz and bias of 5 V, the resultant noise equivalent power (NEP) of n−-GaN Schottky photodetectors with TiW electrodes was1.033×10-12 W, corresponding to a detectivity (D*) of1.079×1012 cm-Hz0.5 W−1.

GaN ON SILICON SUBSTRATE WITH AlN BUFFER LAYER FOR UV PHOTODIODE

2012 ◽  
Vol 21 (01) ◽  
pp. 1250014 ◽  
Author(s):  
L. S. CHUAH ◽  
S. M. THAHAB ◽  
Z. HASSAN
Keyword(s):  
Schottky Barrier ◽  
Buffer Layer ◽  
Barrier Height ◽  
Silicon Substrate ◽  
Dark Current ◽  
Schottky Barrier Height ◽  
Buffer Layers ◽  
Current Ratio ◽  
Principal Mechanism ◽  
Aln Buffer

Nitrogen plasma-assisted molecular beam epitaxy (PAMBE) deposited GaN thin films on (111) n-type silicon substrate with different thickness AlN buffer layers are investigated and distinguished by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman scattering. The thickness of AlN buffer layer ranged from 200 nm to 300 nm. Besides that, the electrical characteristics of the GaN thin film for ultraviolet detecting utilizations are studied by calculating the photo current/dark current ratio on a metal-semiconductor-metal (MSM) photodiode with and without the illumination of Hg-lamp source. The devices have been tested over room temperature (RT). The photocurrent analysis, together with the study of Schottky barrier height (SBH) development, ascertain that the principal mechanism of photo transport is thermionic emission. The photocurrent value is rigorously dependent on Schottky barrier height. The GaN/AlN(200 nm)/n-Si MSM photodiode produces the highest photo/dark current ratio for the lowest strain that consists of the GaN film grown on the AlN (200 nm) buffer layer.

Graphene-Silicon Heterojunction Infrared Photodiode at 1.3/1.55 μm

2016 ◽  
Vol 858 ◽  
pp. 1153-1157
Author(s):  
Tzu Min Ou ◽  
Tomoko Borsa ◽  
Bart van Zeghbroeck
Keyword(s):  
Schottky Barrier ◽  
Quantum Efficiency ◽  
Silicon Photonics ◽  
Dark Current ◽  
Internal Quantum Efficiency ◽  
Noise Equivalent Power ◽  
Absorbing Medium ◽  
Infrared Photodiode ◽  
Gain Energy ◽  
Potential Use

A novel infrared photodiode based on a graphene/n-type silicon heterojunction is explored. The heterojunction photodiode of interest has a large Schottky barrier that results in a low dark current. Graphene serves as the absorbing medium at a wavelength for which silicon is transparent. Under infrared illumination, photo-excited electrons in the graphene gain energy and thus have a greater probability to overcome the barrier and contribute to the photocurrent. We have demonstrated photodiode operation of a graphene/n-Si heterojunction at 1.3 and 1.55 μm wavelength, with 14% internal quantum efficiency and 1.5 pW/Hz1/2 noise-equivalent power, for potential use in silicon photonics.

Microcrystalline (Si,Ge):H Solar Cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Jianhua Zhu ◽  
Vikram L. Dalal
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Quantum Efficiency ◽  
Fill Factor ◽  
Open Circuit Voltage ◽  
Defect Density ◽  
Cell Structure ◽  
Open Circuit ◽  
Base Layer ◽  
Ecr Plasma

AbstractWe report on the growth and properties of microcrystalline Si:H and (Si,Ge):H solar cells on stainless steel substrates. The solar cells were grown using a remote, low pressure ECR plasma system. In order to crystallize (Si,Ge), much higher hydrogen dilution (∼40:1) had to be used compared to the case for mc-Si:H, where a dilution of 10:1 was adequate for crystallization. The solar cell structure was of the p+nn+ type, with light entering the p+ layer. It was found that it was advantageous to use a thin a-Si:H buffer layer at the back of the cells in order to reduce shunt density and improve the performance of the cells. A graded gap buffer layer was used at the p+n interface so as to improve the open-circuit voltage and fill factor. The open circuit voltage and fill factor decreased as the Ge content increased. Quantum efficiency measurements indicated that the device was indeed microcrystalline and followed the absorption characteristics of crystalline ( Si,Ge). As the Ge content increased, quantum efficiency in the infrared increased. X-ray measurements of films indicated grain sizes of ∼ 10nm. EDAX measurements were used to measure the Ge content in the films and devices. Capacitance measurements at low frequencies ( ~100 Hz and 1 kHz) indicated that the base layer was indeed behaving as a crystalline material, with classical C(V) curves. The defect density varied between 1x1016 to 2x1017/cm3, with higher defects indicated as the Ge concentration increased.

High-Bright InGaN Multiple-Quantum-Well Blue Light-Emitting Diodes on Si (111) Using AlN/GaN Multilayers with a Thin AlN/AlGaN Buffer Layer

2003 ◽  
Vol 42 (Part 2, No. 3A) ◽  
pp. L226-L228 ◽  
Author(s):  
Baijun Zhang ◽  
Takashi Egawa ◽  
Hiroyasu Ishikawa ◽  
Yang Liu ◽  
Takashi Jimbo
Keyword(s):  
Quantum Well ◽  
Buffer Layer ◽  
Blue Light ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Algan Buffer

Epitaxial GaN Layer Growth Using Nitrogen Enriched TiN Buffer Layers

2006 ◽  
Vol 916 ◽  
Author(s):  
Kazuhiro Ito ◽  
Yu Uchida ◽  
Sang-jin Lee ◽  
Susumu Tsukimoto ◽  
Yuhei Ikemoto ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Light Emission ◽  
Chemical Vapor ◽  
Nucleation Site ◽  
Layer Growth ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Nitrogen Enrichment ◽  
Threading Dislocation ◽  
Sapphire Substrates

AbstractAbout 20 years ago, the discovery of an AlN buffer layer lead to the breakthrough in epitaxial growth of GaN layers with mirror-like surface, using a metal organic chemical vapor deposition (MOCVD) technique on sapphire substrates. Since then, extensive efforts have been continued to develop a conductive buffer layer/substrate for MOCVD-grown GaN layers to improve light emission of GaN light-emitting diodes. In the present study, we produced MOCVD-grown, continuous, flat epitaxial GaN layers on nitrogen enriched TiN buffer layers with the upper limit of the nitrogen content of TiN deposited at room temperature (RT) on sapphire substrates. It was concluded that the nitrogen enrichment would reduce significantly the TiN/GaN interfacial energy. The RT deposition of the TiN buffer layers suppresses their grain growth during the nitrogen enrichment and the grain size refining must increase nucleation site of GaN. In addition, threading dislocation density in the GaN layers grown on TiN was much lower than that in the GaN layers grown on AlN.

scholarly journals Inverted ternary OPD based on PEIE

2021 ◽  
Author(s):  
Tao An ◽  
Suiyang Liu
Keyword(s):  
Buffer Layer ◽  
Quantum Efficiency ◽  
Active Layer ◽  
Broad Spectrum ◽  
External Quantum Efficiency ◽  
Optical Power ◽  
Organic Photodetector ◽  
Cathode Buffer Layer ◽  
Diode Mode ◽  
Conventional Device

Abstract This paper proposes an inverted ternary organic photodetector (OPD), whose structure is ITO/PEIE/PC61BM/P3HT:PCPDTBT/MoO3 /Al. The use of PEIE as the cathode buffer layer avoids the influence of acidic PEDOT:PSS on the surface and life of the conventional device . The preparation of the ternary active layer ensures the photoelectric characteristics of the device in the visible-infrared broad spectrum range. In this experiment, the effect of PEIE thickness on the working mode of the device was studied by changing the concentration of the spin-coated PEIE solution. Finally, when the solution of PEIE is less than 0.45wt%, the device works in the diode mode, on the contrary, it works in the photoconductive mode. And under 550nm illumination (optical power 4.02mW/cm2) , the device achieves a responsivity of 1.64A/W and an external quantum efficiency of 370%.

scholarly journals Demonstration of Planar Type-II Superlattice-Based Photodetectors Using Silicon Ion-Implantation

Photonics ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 68
Author(s):  
Arash Dehzangi ◽  
Donghai Wu ◽  
Ryan McClintock ◽  
Jiakai Li ◽  
Alexander Jaud ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Quantum Efficiency ◽  
Current Density ◽  
Dark Current ◽  
Infrared Photodetectors ◽  
Type Ii ◽  
Dark Current Density ◽  
Applied Bias ◽  
Type Ii Superlattice ◽  
Specific Detectivity

In this letter, we report the demonstration of a pBn planar mid-wavelength infrared photodetectors based on type-II InAs/InAs1−xSbx superlattices, using silicon ion-implantation to isolate the devices. At 77 K the photodetectors exhibited peak responsivity of 0.76 A/W at 3.8 µm, corresponding to a quantum efficiency, without anti-reflection coating, of 21.5% under an applied bias of +40 mV with a 100% cut-off wavelength of 4.6 µm. With a dark current density of 5.21 × 10−6 A/cm2, under +40 mV applied bias and at 77 K, the photodetector exhibited a specific detectivity of 4.95 × 1011 cm·Hz1/2/W.

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