[OPTICAL REVIEW Vol. 18, No. 1 (2011) 107-110]
© 2011 The Japan Society of Applied Physics
GaN Ultraviolet Schottky Barrier Photodetectors with ZrO2 or SiO2 Insulators
Department of Electronic Engineering, Cheng Shiu University, Kaohsiung 830, Taiwan, R.O.C.
(Received June 1, 2010; Accepted November 17, 2010)
GaN ultraviolet (UV) Schottky barrier photodetectors (PDs) with a ZrO2 or SiO2 layer were successfully fabricated. With an appropriate ZrO2 layer thickness, the dark current of Schottky barrier PDs could be notably suppressed, and the photogenerated carriers could still reach the electrodes by tunneling through the thin ZrO2 layer under illumination. A UV-to-visible rejection ratio of more than one order of magnitude can be found in the Schottky barrier PD with ZrO2 layers. It can be seen clearly that the cut-off occurred at approximately 360 nm while the responses above the band-gap were flat.
Key words: GaN, UV, photodetector, Schottky barrier
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