Study of InGaP/GaAs/InGaP MSM photodetectors using indium-tin-oxide as transparent and antireflection Schottky electrode

We report the performance of InGaP/GaAs/InGaP metal-semiconductor-metal pho todetectors (MSM-PD's) using indium-tin-oxide (ITO) as transparent and anti reflection Schottky electrode. The dark current and photoresponsivity of ab out 60 pA (i.e. 2.4 mu A cm(-2)) and 0.58 A W-1 at 5 V bias for a 50 x 50 m u m(2) photosensitive area with 2 mu m fingers and spaces were measured. We demonstrated that the corresponding rise time, fall time, full width at ha lf maximum and 3 dB bandwidth of temporal responses were 26.4, 134.6, 44.6 ps and 7.0 GHz, respectively. The results of InGaP/GaAs/InGaP MSM-PD's with an ITO Schottky electrode were compared to those of identical geometry dev ices fabricated with a Ti/Pt/Au Schottky electrode. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.