Study on the defect energy levels of high resisitivity In-doped CdZnTe crystals

Samples with different In dopant concentrations were grown by Low Pressure Vertical Bridgman Method. Low temperature photoluminescence (PL) spectra, Deep Level Transient Spectroscope (DLTS) and high resistivity Hall test were used to study major defects in high resistivity In-doped CdZnTe crystal and its possible compensating mechanism. The PL spectra showed that in the In-doped CdZnTe samples of high resistivity, In dopants occupied Cd vacancies, which would exist in undoped CdZnTe crystal, forming shallow donor defect [In-Cd(+)], located at E-c-18meV, and the [In-Cd(+)] interacted with [V-Cd(2-)] to form a complex defect [(In-Cd(+)-V-Cd(2-))(-)] at E-v+163meV. The DLTS results showed that a deep level donor defect was found at 0.74eV below the conduction band, representing probably the energy level of antisite defect [Te-Cd]. The results indicated that the electrical properties of In-doped CdZnTe crystals were dominated by a comprehensive compensating consequence among In donor defects, deep level donor defect Te antisites, intrinsic acceptor defect Cd vacancies and other impurities acceptor defects.