Comparison of electrical and luminescence data for the A center in CdTe

We have investigated the electrical and optical properties of the deep levels responsible for the 1.4–1.5 eV luminescence band usually observed in II–VI compounds. We compared the energy levels found by cathodoluminescence and junction spectroscopy methods for semi-insulating ~CdTe:Cl and Cd0.8Zn0.2Te! and semiconducting samples ~undoped CdTe!. The techniques utilized were deep level transient spectroscopy ~DLTS! on semiconducting samples and photoinduced current transient spectroscopy and photo-DLTS on high resistivity materials. These last two techniques are complementary and allow the determination of the trap character ~donor/acceptor!. Three acceptor levels are seen in the electrical transient data at Ev10.12, 0.14, and 0.16 eV with hole capture cross sections of 2310, 1310, and 4310 cm, respectively. The lowest level is seen only in Cl doped material corroborating the literature optical and electron spin resonance identification of a level at Ev10.12 eV as being a VCd1ClTe donor–acceptor pair center. All three levels may be present in the 1.4 eV luminescence band. © 1996 American Institute of Physics. @S0003-6951~96!04949-2#