Surface passivated function of GaAs MSM-PDs using photoelectrochemical oxidation method

To improve the performance of GaAs metal-semiconductor-metal photodetectors (MSM-PDs), we directly grew an oxide passivation layer in regions between the interdigitated electrodes of MSM-PDs, using the photoelectrochemical oxidation method. The measured dark current of passivated MSM-PDs was comparatively lower than that of unpassivated devices for all of the applied voltages. The breakdown voltages of MSM-PDs with and without oxide passivation layer were 52.5 and 42.5 V, respectively. The benefits of incorporating the oxide passivation layer will possibly lead to a sizable reduction of surface states that in return will help to decrease the probability of surface breakdown. Also, it should improve the rejection ratio of MSM-PDs.