Temperature dependence of current-voltage characteristics of MoS2/Si devices prepared by the chemical vapor deposition method

Layers of MoS2 are directly deposited on the n-type Si (n-Si) substrate by chemical vapor deposition for fabricating a MoS2/n-Si heterojunction device. The rectification current-voltage (I-V) characteristics of MoS2/n-Si devices were measured in the temperature range from 80 to 300 K in steps of 20 K. The temperature-dependent forward-bias I-V characteristics can be explained on the basis of the thermionic emission theory by considering the presence of the interfacial inhomogeneous barriers at the MoS2/n-Si interfaces. The dominance of the induced carrier capture/recombination by states at the MoS2/n-Si interface that lead to the formation of the inhomogeneous barriers serves to influence the photo-response at room temperature. The fabricated MoS2/n-Si devices exhibit reversible switching between high and low current densities, when the simulated sunlight is turned on and off. The sensitivity of the I-V characteristics to temperature provides an opportunity to realize stable and reliable rectification behaviors in the MoS2/n-Si devices. It is found that the electron mobility in the n-Si layer reduces as temperature increases, which leads to the noticeably increased value of the series resistance of MoS2/n-Si devices.