Optical and electrical investigations of imperfection levels in Zn 3P 2

Abstract

Imperfection levels in Zn 3P 2, were investigated by optical and electrical methods. Zn 3P 2 crystals with different hole concentrations within the range 10 13–10 17cm −3 were used. A set of acceptor levels was observed at 0.05, 0.17, 0.27 and 0.36 eV. Deep levels were found at 0.55, 0.66 and 0.85 eV. The absorption processes connected with these levels were successfully described by the quantum defect method. Spectral measurements of absorption as well as photoconductivity were used to investigate the optical transitions in the 1.25–1.60eV energy range. The measured spectra gave a set of energies consistent with the ones ascribed to the expected transitions. Native defects, namely phosphorous interstitials and zinc vacancies, were taken to be the origin of the acceptor levels in Zn 3P 2. Deep, compensating levels were proposed to be the result of phosphorous vacancies and zinc interstitials.