Performance enhancement and optimization of IR graphene/semiconductor hybrid devices

Abstract

Currently, photodetector in IR is used in wide area such as optical communication area, autonomous car, distance sensor, medical sensor device. However, in the case of the semiconductor used in the commercialized IR photodetector, a complicated process and an expensive cost have become a problem. On the other hand, graphene photodetector has the advantages of being able to react in a wide wavelength range, transparent, flexible, and operating at a high speed, so graphene photodetector has been actively studied. Despite these advantages, graphene photodetectors face several limitations that make it difficult to replace other photodetectors. Because graphene is a material without a band gap, it exhibits high dark current in the absence of light, and its low optical absorption results in a responsivity about 100 times lower. Furthermore, its response speed is quite slow, making it difficult to be used as an ideal photodetector. Another common drawback of devices using 2D materials is the difficulty in fabricating sensors on a large area wafer scale. In this dissertation, based on an understanding of optoelectronics, research on a practically usable graphene/semiconductor heterojunction-based photodetector that overcomes the aforementioned issues is presented.