Evaluation of Aging Effects of Zinc Oxide on the Optical Properties of Porous Silicon-Zinc Oxide Heterojunction Photodetector Device

Abstract

Porous silicon is very important for integrated technology because of its many superior properties, such as suitability for mass production, easy and controlled production, and adjustable electrical and optical properties. Semiconductors with metal oxides, such as indium oxide, indium tin oxide, tin oxide, and zinc oxide, are highly preferred in optical devices. Among these metal oxides, zinc oxide is preferred for photodetectors because of its stable crystal structure and large exciton binding energy of 60 meV. Researchers have conducted studies on photodetectors with porous silicon-zinc oxide heterojunction structures. The importance of the stable operation of devices has been emphasized. Therefore, in this study, a porous silicon-based zinc oxide heterojunction structure suitable for photodetector production was formed, and the effect of aging on zinc oxide was investigated over time. As a result of the investigation, it was observed that the intensity decreased approximately 2.5 times at the end of 365 days owing to the aging of zinc oxide. In addition, UV spectroscopy measurements were performed to investigate the optical properties that affect their operation as photodetectors. Because the PS-ZnO heterojunction functions as a detector in the UV region, the absorption and reflectivity of the PS-ZnO heterojunction were investigated, especially in the UV region. From the measurements, it was observed that aging decreased absorption and increased reflectance. These findings underscore the negative impact of aging on photodetector performance.