A new mechanism of low-temperature radiative recombination in bulk crystals of β-InSe and thin films exfoliated from them, resulting in the appearance of intense anti-Stokes luminescence with a photon energy of 2.54 eV, is revealed. The position of the corresponding spectral line is close to the exciton resonance of the k-space-direct band-to-band transition associated with the recombination of electrons at the bottom of the conduction band and holes in the Se p_xy orbitals. The observed anti-Stokes emission presumably results from Auger recombination of k-space-indirect electron—hole pairs, which leads to the population of the lower lying states in the valence band. It is established that the relative intensity of anti-Stokes luminescence increases by more than two orders of magnitude in InSe films with thicknesses of several tens of nanometers as compared to bulk InSe.

揭示了β-InSe块状晶体和从中剥离的薄膜中低温辐射复合的新机制，从而导致出现了强反斯托克斯发光，光子能量为2.54 eV。相应的光谱线的位置靠近的激子共振ķ与电子在导带和空穴在SE底部的复合有关-space直接能带-能带跃迁p _XY轨道。观察到的抗斯托克斯发射可能是由于k的俄歇重组造成的-空间间接电子-空穴对，导致价带中处于低价态的电子占据。已经确定，与块状InSe相比，厚度为几十纳米的InSe膜的抗斯托克斯发光的相对强度增加了两个数量级以上。