Electronic bandgap and exciton binding energy of layered semiconductor TiS3

TL;DR

This study investigates the electronic and optical properties of layered TiS3, revealing a large exciton binding energy comparable to transition metal dichalcogenides, highlighting its potential for optoelectronic applications.

Contribution

The paper combines experimental measurements and theoretical calculations to determine the bandgaps and exciton binding energy of TiS3, a largely unexplored layered semiconductor.

Findings

Electronic bandgap of 1.2 eV (experimental)

Optical bandgap of 1.07 eV (experimental)

Exciton binding energy of 130 meV (experimental)

Abstract

We present a study of the electronic and optical bandgap in layered TiS3, an almost unexplored semiconductor that has attracted recent attention because of its large carrier mobility and inplane anisotropic properties, to determine its exciton binding energy. We combine scanning tunneling spectroscopy and photoelectrochemical measurements with random phase approximation and Bethe-Salpeter equation calculations to obtain the electronic and optical bandgaps and thus the exciton binding energy. We find experimental values for the electronic bandgap, optical bandgap and exciton binding energy of 1.2 eV, 1.07 eV and 130 meV, respectively, and 1.15 eV, 1.05 eV and 100 meV for the corresponding theoretical results. The exciton binding energy is orders of magnitude larger than that of common semiconductors and comparable to bulk transition metal dichalcogenides, making TiS3 ribbons a highly interesting material for optoelectronic applications and for studying excitonic phenomena even at room temperature.