The Effect of Electrode Shape on Schottky Barrier and Electric Field Distribution of Flexible ZnO Photodiode

Abstract

Three metal-semiconductor-metal (MSM) ultraviolet flexible self-powered photodiode (PDs) were fabricated, which differed in the shape of the electrodes. Here, the effect of the electrode's shape on the height of the Schottky barrier and the electric field in these PDs was investigated. They were prepared based on porous Zinc Oxide (ZnO) on fiberglass. Different shapes of the electrodes affect the height of the Schottky barrier in each metal-semiconductor contact and provide the basis for the formation of self-powered PDs. It also affects the electric field generated in the PD's bias condition and affects the PD's parameter. They were fabricated using the radio frequency (RF) sputtering technique, and copper electrodes with different shapes and a sample with interdigitated electrodes were created using the printed circuit board (PCB) method. The photocurrent of the sample with circular and rectangular electrodes was equal to 470 μA in 15V bias, which was twice as good as a sample with an interdigitated MSM structure. It also had the best photocurrent at 0V, which is equal to 0.8 μA. This sample had the best response time among these three samples, which was equal to 440 ms. It is noteworthy that the simulation data confirmed the practical results.