Spin-Orbit Splitting in CdS: Se Single Crystals

Calculated values of the spin-orbit splittings from previously measured valence-band splittings in single crystals of CdS and CdSe at liquid-helium temperatures are 0. 065 and 0. 418 eV, \. {}respectively. In this investigation, spin-orbit splittings have been determined for solid solutions of CdS: Se single crystals from transmission measurements on thin platelets at 4. 2^. The single-crystal platelets of approximately 1 thickness were grown from the vapor phase. Measurements which have been made on seven intermediate compositions indicate that the spin-orbit splittings vary in an approximately linear manner with composition. The average deviation from linearity is approximately 10% greater than the experimental uncertainties. It is believed that slight deviations from linearity may be due to (1) the deviation of CdS from the ideal ca ratio in the wurtzite structure and (2) the greater contribution of ionic binding in CdS.