Особенности динамики спектра фотолюминесценции кристалла Cu-=SUB=-3-=/SUB=-In-=SUB=-5-=/SUB=-S-=SUB=-9-=/SUB=- при изменении интенсивности лазерного возбуждения

Abstract

Photoluminescence spectra were studied on a naturally formed surface of a layered Cu3In5S9 crystal upon excitation by nanosecond laser radiation. At relatively low levels of optical excitation intensity, luminescence quenching was observed near a photon energy of 1.636 eV in a narrow energy band near 118 meV. This phenomenon is explained by the formation of bound triplet excitons and their dissociation with the emission of phonons. It is shown that, as the intensity of the optical excitation of the crystal increases, the impurity emission band in the crystal disappears. The photocurrent spectrum of Cu3In5S9 at 295 K is formed by peaks at energies of 1.53 and 1.81 eV. The lifetime of nonequilibrium electrons through fast centers is ~20 ns. From the temperature dependence of the electrical conductivity of the Cu3In5S9 crystal in the range 110–350 K, the activation energies of two donor levels, 0.28 and 0.76 eV, were determined. Keywords: Cu3In5S9, photoluminescence, photocurrent, electrical conductivity.