InGaP/GaAs heterojunction photosensor powered by an on-chip GaAs solar cell for energy harvesting

摘要

In this study, an InGaP/GaAs heterojunction phototransistor (HPT) and a GaAs solar cell were monolithically integrated into an HPT epitaxial wafer, and the battery-free operation of the HPT was demonstrated for energy harvesting. Although the thickness and doping condition of the layers were optimized for the HPT performance, but not for the solar cell performance, the obtained short-circuit current was high enough to operate the InGaP/GaAs HPT in a two-terminal (2T) configuration. A collector photocurrent of 0.63 mA was obtained when the energy-harvesting InGaP/GaAs 2T-HPT was exposed to white light with a power density of 35mW/cm(2), and it linearly increased with the power density. For a potential application of the energy-harvesting InGaP/GaAs HPT as a photosensor in space, the device was irradiated with electrons of 1 MeV energy and 10(15)cm(-2) fluence. No significant degradation of the fabricated energy-harvesting 2T-HPT after the high-energy electron irradiation guarantees its battery-free operation in space. (C) 2016 The Japan Society of Applied Physics