Measurement and evaluation of the defects in Cd1−xZnxTe materials by observing their etch pits in real time

An improved chemical etching method named as etch pit real-time observation (EPRTO) method was proposed for the measurement and evaluation of the defects in Cd1−xZnxTe materials. Unlike the traditional defect chemical etching method in which the etch pits (EPs) are measured after etching with a fixed time, by using EPRTO method, the EPs can be characterized while etching. A special etching apparatus is designed to observe and record the whole formation process of the surface EPs under the infrared transmission microscope (IRTM). The new method can accurately judge the characteristic of every etch pit (EP) formed on the surfaces of Cd1−xZnxTe materials. By using EPRTO method, the EPs corresponding to dislocations and bulk defects can be recognized. The defect EPs and defect residual EPs can be distinguished. The threading lengths of the dislocations (DTLs) in the materials can be measured. A set of more complete and accurate measurement parameters have been proposed to evaluate the defect properties of Cd1−xZnxTe materials, which can provide a more effective means for studying the correlations of material defect properties with crystal growth technology and device performance.