Structure, Opto-electrical and Thermoelectric Properties of Multilayer SnS1-xSex (0≤x≤1) with Strong In-Plane Anisotropy

Thalita Maysha Herninda^1*, Ching-Hwa Ho¹

¹Graduate Institute of Applied Science and Technology, National Taiwan University of Applied Science and Technology, Taipei, Taiwan

* Presenter:Thalita Maysha Herninda, email:talita.maysha@gmail.com

Tin-based chalcogenides have recently attracted interest owing to their semiconducting properties such as tunable band gap, high carrier density, and significant Figure of merit. It is widely used in solar cells, optoelectronics, and electronic device applications. In this work, single crystals of the SnS1-xSex series (0≤x≤1) have been grown by chemical vapor transport. From analyzing the XRD patterns and HRTEM image, the series are determined to be crystallized in orthorhombic structure regarded as distorted NaCl-type. This structure results in anharmonic and strongly anisotropic properties of SnS1-xSex series. The lattice parameters of the series are evaluated and discussed. Angular-dependent polarized Raman was observed and showed four vibrational modes with noticeable changes depending on the polarization angle, verifying their in-plane anisotropy behavior. The band gap transition has been obtained from thermoreflectance measurement, which varies from 0.94 eV for SnSe to 1.23 eV for SnS. The Hall effect, resistivity and thermoelectric were carried out in the temperature range 20K to 300K. According to the results, SnS1-xSex series are p-type semiconductors in nature with carrier concentration of about 10¬17 cm-3. SnSe achieved the highest ZT value with ZT of 0.44. These findings represent that SnS1-xSex series could be low-cost and environmentally friendly thermoelectric material.

Keywords: 2D Semiconductor, Chemical Vapor Transport, Optical Properties, Thermoelectric Properties, Raman Spectroscopy