Synthesis of MoS2 Atomic Layer using PECVD

Graphene has become to be the most spotlighted material because it has remarkable characteristics and advantages. Despite of these advantages, Graphene is difficult to apply to semiconductor devices because of low on/off ratio respectively with zero band-gap. However, since molybdenum disulfide (MoS 2 ) has the band gap of 1.96 eV in bulk state as well as the similar property with graphene, it can apply to semiconductor devices. Moreover single layer of MoS 2 has high mobility as 200cm 2 /v -1 s -1 and on/off ratio over 10 8 . MoS 2 is usually synthesized by Chemical Vapor Deposition (CVD) under the relatively high temperature to get high quality property. However, the CVD method has limitation to synthesis of MoS 2 on flexible plastic substrate which has a melting point about 200 o C. Therefore, it is very important to characterize the MoS 2 synthesis methods of low temperature. In this study, MoS 2 was deposited by Plasma Enhanced CVD (PECVD) under the process temperature from 150 o C to 200 o C with Mo thin film and H 2 S gas precursor. Mo was deposited on SiO 2 /Si wafer with 1 nm thickness by e-beam evaporator firstly, and then decomposed H 2 S gas by plasma was used for S precursors. Synthesized MoS 2 thin films at 150 o C exhibited the two characteristic MoS 2 raman peaks. In this experiment, synthesis of MoS 2 layer by 2 conditions and we confirmed the synthesis MoS 2 by raman spectroscopy. Raman spectroscopy has been widely used to determine the number of layers, as well as material property.