High-performance solar-blind photodetectors based on AlxGa 1_xN heterostructures

Date
2004
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Source Title
IEEE Journal on Selected Topics in Quantum Electronics
Print ISSN
1077-260X
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Publisher
IEEE
Volume
10
Issue
4
Pages
742 - 751
Language
English
Type
Article
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Abstract

Design, fabrication, and characterization of high-performance AI xGa1-xN-based photodetectors for solar-blind applications are reported. AlxGa1-xN heterostructures were designed for Schottky. p-i-n, and metal-semicondnctor-metal (MSM) photodiodes. The solar-blind photodiode samples were fabricated using a microwave compatible fabrication process. The resulting devices exhibited extremely low dark currents. Below 3 fA, leakage currents at 6-V reverse bias were measured on p-i-n samples. The excellent current-voltage (I-V) characteristics led to a detectivity performance of 4.9×1014 cmHz1/2W -1. The MSM devices exhibited photoconductive gain, while Schottky and p-i-n samples displayed 0.09 and 0.11 A/W peak responsivity values at 267 and 261 nm, respectively. A visible rejection of 2×104 was achieved with Schottky samples. High-speed measurements at 267 nm resulted in fast pulse responses with greater than gigahertz bandwidths. The fastest devices were MSM photodiodes with a maximum 3-dB bandwidth of 5.4 GHz.

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Keywords
Algan, Detectivity, Heterustructure, High speed, Metal-semiconductor-metal (MSM), P-i-n, Photodetector, Schottky, Solar blind, Ultraviolet, Bandwidth, Electric currents, Fabrication, Photoconductivity, Photodetectors, Photodiodes, Semiconducting aluminum compounds, Semiconducting gallium compounds, Solar energy, Voltage measurement, AlGaN, Detectivity, High speed, Metal-semiconductor-metal (MSM), Solar blind, Heterojunctions
Citation
Published Version (Please cite this version)