(INVITED) Opto-electronic properties of solution-synthesized MoS2 metal-semiconductor-metal photodetector

Abstract

We report a simple fabrication method for metal-semiconductor-metal (MSM) photodetectors using solution-synthesized MoS2 films as the semiconductor channel and pure indium for the metal contacts. Resonance Raman spectroscopy has been used to confirm the growth of ultra-thin MoS2 films. Due to the low work function of indium, the back-to-back indium-MoS2 Schottky junctions formed relatively low Schottky barrier height (0.43 eV), which has been calculated using the thermionic field emission model. Moreover, the MSM device shows good responsivity (22 mA/W) under white light illumination. The MoS2-MSM device possesses higher photoelectrical response in the visible and near IR region compared to UV due to the indirect bandgap of ultra-thin MoS2 film which has been estimated to be 1.38 eV. These findings reveal the significance of using low work function metals like indium as contacts for layered transition metal dichalcogenides (TMDC) films (produced by low cost solution-based techniques), particularly MoS2, in order to design semiconductor devices with efficient opto-electronic performance.

Keywords

• MSM photodetector
• MoS2
• Schottky contacts