Passivated the Surface of GaAs Photodetectors Using the Photoelectrochemical Oxidation Method

To improve the stability of GaAs metal-semiconductor-metal photodetectors (MSM-PDs), we directly grow the oxide of semiconductor between the interdigital electrodes of MSM-PDs for a passivation layer, using the photoelectronchemical oxidation method. The dark currents of passivated MSMI (with a In0.5(Al0.66Ga0.34) 0.5P capping layer) and MSM2 (without a capping layer) were lower than for unpassivated devices, for all applied voltages. The breakdown voltage of the oxide passivated MSMI was 52.5V and the unpassivated MSMI was 42.5 V. It can also reduce the surface states to improve the rejection ratio of MSM-PDs.