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Title: Mechanism for Long Photocurrent Time Constants in α-Ga 2 O 3 UV Photodetectors
Deep centers and their influence on photocurrent spectra and transients were studied for interdigitated photoresistors on α -Ga 2 O 3 undoped semi-insulating films grown by Halide Vapor Phase Epitaxy (HVPE) on sapphire. Characterization involving current-voltage measurements in the dark and with monochromatic illumination with photons with energies from 1.35 eV to 4.9 eV, Thermally Stimulated Current (TSC), Photoinduced Current Transients Spectroscopy (PICTS) showed the Fermi level in the dark was pinned at E c −0.8 eV, with other prominent centers being deep acceptors with optical thresholds near 2.3 eV and 4.9 eV and deep traps with levels at E c −0.5 eV, E c −0.6 eV. Measurements of photocurrent transients produced by illumination with photon energies 2.3 eV and 4.9 eV and Electron Beam Induced Current (EBIC) imaging point to the high sensitivity and external quantum efficiency values being due to hole trapping enhancing the lifetime of electrons and inherently linked with the long photocurrent transients. The photocurrent transients are stretched exponents, indicating the strong contribution of the presence of centers with barriers for electron capture and/or of potential fluctuations.  more » « less
Award ID(s):
1856662
PAR ID:
10405661
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
ECS Journal of Solid State Science and Technology
Volume:
12
Issue:
4
ISSN:
2162-8769
Page Range / eLocation ID:
045002
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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