Study on the Defect Energy Levels of High Resisitivity In-doped CdZnTe Crystals

Abstract

Samples with different In dopant concentrations were grown by Low Pressure Vertical Bridg- man 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~(2-)_(Cd)]to form a complex defect[(In~+_(Cd)-V~(2-)_(Cd))-]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 de- fects,deep level donor defect Te antisites,intrinsic acceptor defect Cd vacancies and other impurities acceptor defects.