Indium (III) selenide is currently one of the most actively studied materials in the two-dimensional family due to its remarkable ferroelectric and optical properties. This study focuses on the luminescent properties of few-layer In2Se3 flakes with thicknesses ranging from 7 to 100 monolayers. To explore the photoluminescence features and correlate them with changes in crystal symmetry and surface potential, we employed a combination of techniques, including temperature-dependent micro-photoluminescence, time-resolved photoluminescence, Raman spectroscopy, atomic force microscopy, and Kelvin probe force microscopy. X-ray diffraction and Raman spectroscopy confirmed that the samples studied possess the α-polytype structure. The micro-photoluminescence spectrum consists of two bands, A and B, with band B almost completely disappearing at room temperature. Temperature-dependent photoluminescence and time-resolved measurements helped us to elucidate the nature of the observed bands. We find that peak A is associated with emission from interband transitions in In2Se3, while peak B is attributed to defect-related emission. Additionally, the photoluminescence decay times of In2Se3 flakes with varying thicknesses were determined. No significant changes were observed in the decay components as the thickness increased from 7 to 100 monolayers, suggesting that there are no qualitative changes in the band structure.
@article{arxiv.2502.03981,
title = {Photoluminescence Features of Few-Layer Hexagonal $\alpha$-In$_2$Se$_3$},
author = {I. A. Eliseyev and A. I. Veretennikov and A. I. Galimov and L. V. Kotova and G. V. Osochenko and K. A. Gasnikova and D. A. Kirilenko and M. A. Yagovkina and Yu. A. Salii and V. Yu. Davydov and P. A. Alekseev and M. V. Rakhlin},
journal= {arXiv preprint arXiv:2502.03981},
year = {2025}
}