Effects of temperature and pressure on the optical and vibrational properties of thermoelectric SnSe

Abstract

We have conducted a comprehensive investigation of the optical and vibrational properties of the binary semiconductor SnSe as a function of temperature and pressure by means of experimental and ab initio probes.

Spectroscopic trace of the Lifshitz transition and multivalley activation in thermoelectric SnSe under high pressure

“…For both samples, the semimetallic high-pressure phase originates from a change in the atomic coordinate z of the Sn atom along the c axis. Although the sample remains in the Pnma space group 31,34,47 , the c axis shows more drastic compression than the other axes 47 . In particular, within the scope of the calculations, only adjusting the lattice parameter does not lead to a metallic phase, even up to 10 GPa.…”

“…At 0.86 GPa, the compound transforms from a two-valley system to a four-valley system, accompanied by improved thermoelectric properties, providing proof that pressure is a powerful tool to tune the electronic multivalley 27,28 . Densityfunctional theory (DFT) calculations and transport studies have reported enhanced thermoelectric properties of SnSe upon application of external pressure [29][30][31][32] . Although transport measurements 33,34 and theoretical approaches 35,36 provide evidence for a semiconductor-semimetal transition, direct investigations of the electronic structure and its pressure dependence are still lacking.…”

High‐Performance Thermoelectric SnSe: Aqueous Synthesis, Innovations, and Challenges

“…Sn/Se vacancies can significantly improve S 2 σ by tuning n / p to their optimized values, which can be explained and guided by the variation of their band structures 207,213,234,268,269,272–298. Taking Sn vacancy for example, Figure 7c,d compares the calculated band structures for SnSe and Sn 1− x Se (here x = 0.008 is used), respectively, and Figure 7e compares DOS based on DFT calculations 197.…”

Effect of film thickness and evaporation rate on co-evaporated SnSe thin films for photovoltaic applications

“…Due to the excellent electronic and optical properties of binary compounds in transition metals, many scholars have conducted in-depth research in photovoltaic and solar-cell systems. [1][2][3][4][5] Among binary compounds in transition metals, SnSe has great application prospects because SnSe has an orthorhombic crystal structure, 6 which is suitable for solar cells. SnSe is a p-type semiconductor and its high absorption coefficient (10 5 cm À1 ) ensures that solar radiation is absorbed almost completely.…”