Edge Emission in CdS as Internal Radiative Transition in Donor‐Acceptor Associates

Abstract

Abstract The short‐wavelength series of the edge emission of CdS single crystals is studied in the temperature range 18 to 150 °K with respect to (i) band shape, (ii) dependence of the half‐width of the components on temperature and excitation intensity, (iii) temperature dependence of the peak position of the zero‐phonon component, (iv) of the polarization ratio, and (v) of the luminescent intensity. It is concluded that this emission is due to an internal electronic transition occurring in nearest‐neighbour donor‐acceptor associates. The half‐width of the components is ascribed to 5 meV‐phonon and centre‐centre interaction. The polarization ratio I E⊥c /I E∥︁c is interpreted as due to a temperature dependent distribution of the associates over the possible directions of orientation in the crystal.