Photoluminescence study of cadmium zinc telluride

Abstract

In this thesis, I present a detailed study of Cd1-xZn xTe crystals with 0 ≤ x ≤ 0.14 using photoluminescence (PL) spectroscopy in the temperature range from 5 K to 300 K with the purpose of: (1) identifying various radiative transitions that are signatures of various point defects in bulk CdZnTe, (2) determining the zinc concentration in these crystals, and (3) identifying the nature of room-temperature PL. PL spectra at 5 K was used to determine the bandgap and hence the zinc concentrations. In the current state-of-the-art CZT grown for radiation detectors, it is common to observe 5-K PL spectra dominated by donor-bound exciton emission (D 0, X). Also, a deep acceptor-bound exciton (A0, X) related to a complex associated with Cd vacancies is usually detected. Thus, it was of interest to determine whether the new trend in bulk CZT growth would produce a different conclusion about the origin of the 300-K PL