Low Temperature Annealing Effects on Radio-Frequency-Sputtered Tungsten Disulfide Layers on Soda-Lime Glass Substrates

Abstract

To lower the fabrication cost in the direct formation of 2-dimensional (2D) transition metal dichalcogenide (TMDC) materials on substrates, tungsten disulfide (WS2) layers were deposited on soda-lime glass substrates instead of sapphire glass substrate by radio-frequency (RF) sputtering and rapid thermal annealing (RTA) was carried out at temperatures lower than 600 degrees C (from 400 degrees C to 550 degrees C). From the scanning electron microscope (SEM) and atomic force microscope (AFM) images, it was possible to observe much larger bumps on the surface of WS2 on soda-lime glass at higher RF sputtering powers and higher RTA temperatures. The Raman spectra results showed the 2D WS2 layers were formed at the higher RF sputtering powers as a formation of E-2g(1) peak and A(g)(1) peak and the Hall measurement results also showed the carrier mobility was dependent on the RF sputtering powers and RTA temperatures. The structural and electrical characteristics showed that 2D WS2 layers can be directly formed on soda-lime glass substrates at temperatures below 600 degrees C.