Abstract
Recently, as technology has developed rapidly, semiconductor devices are asked to scale down to improve efficiency. However, conventional fabrication processes are encountering their limits (such as “short channel effect”), opening the fields on researches and development of 2D materials. Due to the atomic-layered structures and lack of dangling bonds resulted from interlayer van der Waal forces, 2D materials have become candidates for next-generation devices. Among them, compared with graphene, monolayer TMDc not only reveal direct bandgap, high absorption and high quantum efficiency, but also response to spectrum ranged from visible to NIR, being suitable for 2D optoelectronic devices. While TMDc possess high photoresponsivity, longer response time limit their application for photodetecting. It is necessary to conduct further researches, and modify fabrication processes to improve their performance. In this work, analysis on the factors that affect optoelectronic properties of TMDc was highlighted. By modifying the processes, better electronic properties were obtained, and then induced better optoelectronic properties. Wavelength 633 nm red laser was used in this work to determine the changes in transport behavior under illumination, and the factors affecting the transport properties, such as atmosphere, light source, bias, and contact quality, were also discussed through time-resolved and power-dependence profiles for improvement of decay speed. Moreover, graphene/MoS2 heterostructures were fabricated, and charges transfer phenomenon across heterojunction was also observed, resulting in persistent photocurrent that provides a platform for further applications.