Paper
1 July 1998 Structural defects and impurities on CZT crystals
Haim Hermon, Colin Hackett, Ed Tarver, Eilene S. Cross, Nancy Yang, Ralph B. James, Michael M. Schieber, Vitaliy K. Komar, Nikolai N. Kolesnikov
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Abstract
Various types of precipitates and grain boundaries have been studied in Cd1-xZnxTe (CZT). In this study we used elemental analysis methods such as scanning electron microscopy (SEM), microprobe analysis, inductively coupled plasma mass spectroscopy (ICP/MS) and the new laser ablation ICP/MS methods. Transient charge technique was applied for the first time of CZT crystals for evaluating the electrical transport properties of semiconductors. Another method, IR transmission spectroscopy, enables us to evaluate the microstructure defects and then to correlate this with impurity level and electrical properties in order to have a better understanding of the requirements to improve the yield for large volume CZT spectrometers. We have evaluated crystals from the former Soviet Union, which have high concentration of defects. Precipitates and grain boundaries rich with carbon were observed in CZT crystals. Electrical transport properties such as (mu) (tau) (mobility-lifetime product) were measured and correlated with the chemical physical defects, as observed by IR transmission. On crystals rich with many microstructures, as shown by IR transmission, lifetimes below 1 microsecond(s) were measured, compared with 5 - 15 microsecond(s) on the detector grade materials. SEM and microprobe analysis performed on the precipitates gave high values of carbon. However, using laser ablation ICP/MS, a value in the range of 200 - 800 ppm for carbon was measured.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Haim Hermon, Colin Hackett, Ed Tarver, Eilene S. Cross, Nancy Yang, Ralph B. James, Michael M. Schieber, Vitaliy K. Komar, and Nikolai N. Kolesnikov "Structural defects and impurities on CZT crystals", Proc. SPIE 3446, Hard X-Ray and Gamma-Ray Detector Physics and Applications, (1 July 1998); https://doi.org/10.1117/12.312903
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KEYWORDS
Crystals

Carbon

Laser ablation

Sensors

Scanning electron microscopy

Photomicroscopy

Pulsed laser operation

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