GHz response of metamorphic InAlAs metal–semiconductor–metal photodetector on GaAs substrate

Abstract

We fabricated metal–semiconductor–metal (MSM) photodetectors on the metamorphic InAlAs layer grown on a GaAs substrate. The devices were measured at a wavelength in the 0.8 µm regime. The receiving area is 30 × 30 µm2 and the electrode spacings are 2, 1, and 0.4 µm. At the electrode spacing of 1 µm, a dark current of 125 nA was obtained at a bias voltage of −15 V. At a wavelength of 830 nm, a responsivity of 0.13 A/W was obtained at a bias voltage of −15 V. At a wavelength of 850 nm, the maximum bandwidth of 9 GHz was obtained at a bias voltage of −15 V.