Band structure of a IV-VI black phosphorus analogue, the thermoelectric SnSe

TL;DR

This paper investigates the band structure of SnSe, a black phosphorus analogue, revealing highly anisotropic valence bands with multiple valleys, which are promising for thermoelectric applications.

Contribution

It provides the first detailed measurement of SnSe's band structure, highlighting its anisotropic valleys relevant for thermoelectric efficiency.

Findings

SnSe has highly anisotropic valence bands

Multiple valleys with fast in-plane dispersion

Negligible out-of-plane dispersion

Abstract

The success of black phosphorus in fast electronic and photonic devices is hindered by its rapid degradation in presence of oxygen. Orthorhombic tin selenide is a representative of group IV-VI binary compounds that are robust, isoelectronic, and share the same structure with black phosphorus. We measured the band structure of SnSe and found highly anisotropic valence bands that form several valleys having fast dispersion within the layers and negligible dispersion across. This is exactly the band structure desired for efficient thermoelectric generation where SnSe has shown a great promise.