HIGH-DENSITY EXCITATION EFFECT OF THE INDIRECT BAND LUMINESCENCE IN THALLOUS HALIDES

A broad band luminescence is observed at the indirect gap region in hi ghly purified TlBr and TlCl crystals under high density excitation. Fr om the analysis of the line shape, power dependence, lifetime and some characteristic features of the luminescence, it is discussed the poss ibility that the luminescence is associated with an LA-phonon assisted indirect recombination (X(6)(+)-R(6)(-)) of electron-hole liquid (EHL ). Equilibrium density, binding energy and other parameters of EHL are estimated and it is presumed that the hole-phonon scattering is domin ant in their recombination process.