Strong quantum confinement effect in the optical properties of ultrathin {\alpha}-In2Se3

TL;DR

This study reveals a significant quantum confinement effect in ultrathin { extalpha}-In2Se3 crystals, showing a large thickness-dependent shift in optical band gap, which is among the most substantial observed in semiconductor 2D materials.

Contribution

It demonstrates the pronounced quantum confinement effect in ultrathin { extalpha}-In2Se3 and reports the largest band gap variation among 2D semiconductors.

Findings

Large thickness-dependent optical band gap shift observed

Band gap variation among the largest in semiconductor crystals

Shift spans a region of the near-UV spectrum

Abstract

The effect of quantum confinement in the optical absorption spectra of atomically thin {\alpha}-In2Se3 crystals is studied, observing a huge thickness-dependent shift in the optical band gap of exfoliated {\alpha}-In2Se3 flakes. The band gap variation reported here is among the largest found in semiconductor crystals and spans a region of the near-UV spectrum uncovered by other 2D semiconductors.