Backilluminated GaN/AlGaN heterojunction ultraviolet photodetector with high internal gain
Author(s) -
S. K. Zhang,
W. B. Wang,
I. Shtau,
Feng Yun,
Lei He,
H. Morkoç̌,
Xiaocong Zhou,
M. C. Tamargo,
R. R. Alfano
Publication year - 2002
Publication title -
applied physics letters
Language(s) - English
Resource type - Journals
eISSN - 1077-3118
pISSN - 0003-6951
DOI - 10.1063/1.1526166
Subject(s) - photocurrent , responsivity , photodetector , optoelectronics , materials science , heterojunction , ultraviolet , photoconductivity , wide bandgap semiconductor , gallium nitride , trapping , semiconductor , nanotechnology , ecology , layer (electronics) , biology
We report on a backilluminated GaN/Al0.18Ga0.82N heterojunction ultraviolet (UV) photodetector with high internal gain based on metal-semiconductor-metal structures. A narrow band pass spectral response between 365 and 343 nm was achieved. When operating in dc mode, the responsivity reaches up to the order of 102 A/W under weak UV illumination, which is due to enormous internal gain up to 103. The linear dependence of photocurrent on bias and its square root dependence on optical power are found and explained by a trapping and recombination model. The high photocurrent gain is attributed to trapping and recombination centers with an acceptor character induced by dislocations in GaN.
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