EFFECT OF TEMPERATURE, CONCENTRATION OF PRECURSORS AND DISTANCE BETWEEN PRECURSORS ON THE SYNTHESIS OF MOLYBDENUM DISULFIDE (MoS2) USING CHEMICAL VAPOR DEPOSITION (CVD) TECHINQUE- CVD GROWN MONOLAYER MoS2 BASED RRAM

Abstract

Graphene is a semimetal with zero bandgap which has imposed a limit on its applications in field effect transistors and optoelectronics. Owing to this fact, other 2D materials such as h-BN, MXenes, phosphorene, and TMDCs were explored for their potential use in various electronic devices. Two-dimensional (2D) Transition Metal Dichalcogenides (TMDCs) have been engrossing a broad range of scientific interests due to their outstanding properties. Transition metal dichalcogenides (TMDCs) show excellent optical, mechanical, and electronic properties because they have a bandgap that is tunable and they exhibit a transition from indirect to direct bandgaps. Among all the explored TMDCs, MoS2 has been eyeing the most attention. In the present study, monolayer MoS2 has been grown on Si/SiO2 substrate using the Chemical Vapor Deposition (CVD) technique, where MoO2 and sulfur were used as the precursor. We analysed the tractable growth of monolayer MoS2 developing to continuous films from triangular flakes by optimizing several parameters. The sample was further studied using various characterization techniques viz. Optical Spectroscopy, Raman Spectroscopy and Photoluminescence spectroscopy which showed that monolayer MoS2 can be fabricated on Si/SiO2 substrate by maintaining the temperature at 750˚C for 15 to 30 minutes. The two distinctive Raman frequencies of E2g1 and A1g vary persistently with the number of layers of ultrathin MoS2 flakes, whereas the intensity and width of peaks vary inconsistently. Molybdenum disulfide (MoS2) is one of the most quintessential TMDCs with a 1.84 eV direct bandgap in monolayer form which makes it scientifically as well as industrially important. Monolayer MoS2 shows intense photoluminescence because of the quantum confinement effect. We have further studied the switching characteristics of the CVD grown monolayer MoS2 based RRAM device. Silver electrodes were deposited on the grown sample to form a planar MIM structure i.e., Ag/MoS2/Ag. The typical I-V characteristics of the fabricated metal-insulator-metal (MIM) structure were studied using the two-probe measurement technique.