Impact of H2 gas on the properties of MoS2 thin films deposited by sulfurization of Mo thin films

Abstract

MoS2 has gained tremendous interest due to its highlighting electronic and optoelectronic properties. In this work, an attempt has been made to develop a CMOS compatible process for the fabrication of a MoS2 thin film. In the first step, molybdenum (Mo) thin film was deposited on silicon substrate by RF magnetron sputtering. In the second step, chemical vapor deposition (CVD) was used for the synthesis of MoS2 using a custom-designed dual zone tubular furnace. The impact of hydrogen (H2) on the CVD growth of MoS2 thin film was studied with the mixture of H2 and argon (Ar) gas in 1:10 ratio. AFM and FESEM images revealed a uniform and smooth growth of MoS2 films using H2 as a reducing gas. Raman characteristics peaks, observed at 386 cm−1 and 408 cm−1, have confirmed the formation of MoS2 film, which corresponds to the hexagonal coordination (2H). The intensity of photoluminescence peak of MoS2 thin film is found to be increased with hydrogen treatment. Moreover, the impact of H2 gas was systematically studied on the electrical properties and a reduction in the carrier concentration of MoS2 was observed with a flow of 20 sccm H2. A detailed study on the impact of H2 gas and MoS2/Si heterojunction properties were also performed.