Photogating induced high sensitivity and speed from heterostructure of few-layer MoS 2 and reduced graphene oxide-based photodetector.

Over the past few years, two-dimensional transition metal dichalcogenides (2D-TMDC) have attracted huge attention due to their high mobility, high absorbance, and high performance in generating excitons (electron and hole pairs). Especially, 2D molybdenum disulfide (MoS 2 ) has been extensively used in optoelectronic and photovoltaic applications. Due to the low photo-to-dark current ratio ( I photo/dark ) and low speed, pristine MoS 2 -based devices are unsuitable for these applications. So, they need some improvements, i.e. , by adding layers or decorating with materials of complementary majority charges. In this work, we decorated pristine MoS 2 with reduced graphene oxide (rGO) and got improved dark current, I photo/dark , and response time. When we compared the performance of pristine MoS 2 based device and rGO decorated MoS 2 based device, the rGO/MoS 2 -based device showed an improved performance of responsivity of 3.36 A W -1 , along with an I photo/dark of about 154. The heterojunction device exhibited a detectivity of 4.75 × 10 12 Jones, along with a very low response time of 0.184 ms. The stability is also outstanding having the same device performance even after six months.