Extended defects in CdZnTe crystals: Effects on device performance

Characterisation of vapour grown CdZnTe crystals using synchrotron X-ray topography

“…Material defects like dislocations, precipitates, grain boundaries and cracks can have large charge trapping capabilities, thus reducing the charge collection efficiency (CCE) of the detector. This trapped charge can also cause deformation of the internal electric field, resulting in spatial inhomogeneity of the CCE, and thus poor performance in pixelated devices [8,9]. Transmission synchrotron X-ray topography is therefore the ideal technique to characterise such bulk defects in thick single crystals.…”

Study on thermal annealing of cadmium zinc telluride (CZT) crystals

“…CZT's unique properties include a high average atomic number, large bandgap, and good electron-transport properties, along with the availability of materials with acceptable cross-sectional areas and thicknesses. These merits support high detection-efficiency and good energy-resolution when operating at room temperature [1][2][3][4]. However, largely, the development of CZT detectors still is limited by material defects, typically Te inclusions and dislocations.…”

“…Using a delicate X-ray response micro-scale mapping system developed at National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL), we demonstrated, for the first time, that Te inclusions are the major impediment to good energy resolution in long-drift detectors [3]. More recently, we recognized that extended defects, e.g., dislocations, are another important performance-limiting problem, because they also act as trapping centers and lower the carrier-transport properties [4]. Consequently, we expect that before CZT detectors fully reach their potential and demonstrate the desired performance for large-volume devices, we must generate crystals relatively free from large inclusions and dislocations.…”

Selective Etching of ZnхCd1-хTe Single Crystals

“…Для виявлення міжзеренних границь і двійників, а також ідентифікації полярності поверхні (111) Zn x Cd 1-x Te авторами [16][17][18] запропоновано використовувати розчини складу: 1 HF:3 HNO 3 : 4 (2 %-ого водного розчину AgNO 3 ) (розчин 1); 1 HF: 3 HNO 3 :5 (0,5 %-ого водного розчину AgNO 3 ) (розчин 2). Травлення проводять при кімнатній температурі у розчині 1 впродовж 30 -60 сек., а в розчині 2 -10 -15 сек., причому після обробки…”