Optical and EPR study of Ni+(3d9) in ZnS

Abstract
Optical absorption and emission connected with internal transitions of Ni+ (d9) in cubic, faulted and wurtzite ZnS are reported. Zeeman experiments on cubic samples yield g1=0.97 and g2=-0.62 for the 2E excited-state g-factors. Different photoionisations involving the Ni+ charge state are discussed. The behaviour of the EPR spectrum under various experimental conditions is presented and some conclusions are given about the relaxation time as well as a method allowing the detection of the Ni+ EPR spectrum with great sensitivity.