Atomic Scale Investigation of Tin Selenide

Abstract

SnSe is a p type semiconductor belonging to IV-VI group of chalcogenides. It is a layered material with strong in plane covalent interaction and weak inter layer Van der Waal’s interaction. SnSe in Cmcm phase is known for its highest figure of merit (ZT) value of 2.6 at 923K. This behaviour is attributed to its ultra-low thermal conductivity of around 0.24 W/mK. Even though few studies on surface properties of SnSe are reported, the local electronic property of the sample is not investigated thoroughly. In this work, Scanning Tunnelling Microscopy and Scanning Tunnelling Spectroscopy studies were carried out to understand the local electronic properties of the SnSe at 77K and at 300K. SnSe was synthesized using chemical vapour transport technique and studies were performed on Pnma phase of the crystal. Investigation of intrinsic defects on the single crystal was performed in Ultra High Vacuum Low Temperature Scanning Tunnelling Microscopy.