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High‐sensitivity UV phototransistor with GaN/AlGaN/GaN gate epi‐structure
Author(s) -
Okada Masaya,
Matsuura Kazuaki,
Ao JinPing,
Ohno Yasuo,
Kawai Hiroji
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200674735
Subject(s) - photocurrent , optoelectronics , materials science , photodiode , heterojunction , diode , transistor , sensitivity (control systems) , layer (electronics) , photoresistor , active layer , voltage , nanotechnology , thin film transistor , electrical engineering , electronic engineering , engineering
A highly sensitive UV phototransistor was developed using AlGaN/GaN heterojunction field effect transistor (HFET) technology. The phototransistor consisted of a thin undoped GaN layer added on top of a conventional AlGaN/GaN HFET structure. In such a structure, holes generated in the surface i‐GaN layer are accumulated at the GaN/AlGaN interface, and they modulate the electrons in the FET channel. Due to this charge modulation effect, high photocurrent can be obtained. In the structure under study, hole life time was so long that a hole‐evacuating refresh operation was required for fast response and linear sensitivity. When irradiated with UV light of 360 nm, a device with 6 × 10 –4 mm 2 active area produced two hundred times higher photocurrent than a commercial Si UV diode with a much larger area. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)