Photocurrent study on bulk and few layers MoS₂ field effect transistors

Abstract

Atomically thin Molybdenum disulfide, MoS2, a star member of the group VI transition metal dichalcogenide(TMDC) family has been attracting rising interests for its potential applications in emerging electronics and optoelectronics. Bulk MoS2is a semiconductor with an indirect gap located between the top of valence band at Γ points and the bottom of conduction band in mid of K and Γ points in its Brillouin zone. Atomically thin MoS2 films including monolayers and multilayers, being chemically inert, present a class of intrinsic 2D semiconductors which are widely regarded as a platform for ultimate electronics.

As yet tremendous efforts focus on the optical properties and electric transport study. In this thesis, we report the experimental study of photocurrent measurements on MoS2thin films. The sample preparation, device fabrication, optical and electric characterizations are introduced. The experiments have been carried out on a field effect transistor (FET) structured MoS2 device. The photocurrent spectroscopy reveals the interband excitonic transitions at spin-split bands around K valleys. The results demonstrate that MoS2has potential applications in optoelectronics.