22nd International Young Scientists Conference Optics and High Technology Material Science - SPO 2021 ONLINE

Temperature dependence of 2D MoS2 photoconductivity.

13 Nov 2021, 13:00

5m

Online (Taras Shevchenko National University of Kyiv)

Poster Poster Session

Speaker

Mr Mykyta Redkin (Taras Shevchenko National University of Kyiv)

Description

Photoelectric properties of a two monolayer thick (indirect-gap) MoS2 flake with lateral Ag contacts on a SiO2/Si substrate were studied. Photocurrent spectra were obtained with AC technique using a lock-amplifier at temperatures from 10 to 290 K. Apart from a band due to Si substrate, a contribution of MoS2 reveals in the spectra as a broad background of band-to-band transitions and sharp peaks of A and B excitons originating from a spin-orbital split of the valence band. An increase of the exciton contribution with temperature is observed, being followed by a decrease above 110 K. Above 200 K, the exciton peaks transfer to valleys on the background originated from band-to-band transitions. The temperature increase of integral A and B exciton photoresponse with temperature is analyzed in terms of thermal dissociation of the excitons. The exciton binding energy of 680 meV was estimated from the exponential part of temperature dependency.