Аннотация:Abstract An investigation is made of the fundamental absorption edge of single crystals of CdS at 300, 77, and 20.4 °K. The crystals have In and Ga donors, and Cu and Ag acceptors. It is shown that for donor concentrations between 10 18 and 10 19 cm −3 the absorption edge is shifted towards longer wavelengths. The acceptors do not lead to any changes in the absorption edge. The shift of the absorption edge by the donors and its effect on the exciton spectrum is discussed. The effect is thought to be associated with the deformation of the valence band and the formation of the “tail” of the density of states.
