Study of dislocations in CdZnTe single crystals

Experimental studies have been conducted to investigate the influence of dislocations on the properties of CdZnTe crystals. Dislocations were introduced into CdZnTe wafers by means of bending deformation at elevated temperature. The average infrared (IR) transmittance of CdZnTe wafers after deformation is decreased from 64 to 44%. The polarization absorption of dangling-bond electrons in dislocations should be responsible for this decrease of IR transmittance. In photoluminescence measurements, the shallow donor-acceptor pair transition peak at 1.557 eV is detected in CdZnTe after deformation. In the defect-related region, a new band (D _complex) located at 1.508 eV appears, which should be attributed to defect levels introduced by dislocations. Meanwhile, leakage current at 15 V is increased from 10 ^-8 to 10 ^-4 A. The analysis suggests that the leakage current of CdZnTe after deformation is dominated by the Poole-Frenkel effect. Te and Cd dislocations created at two faces introduce different electrical characteristics.