Point defects: Their influence on electron trapping, resistivity, and electron mobility-lifetime product in CdTexSe1−x detectors

• Published in: Journal of applied physics 2016-01, Vol.119 (2)
• Main Authors: Gul, R., Roy, U. N., Egarievwe, S. U., Bolotnikov, A. E., Camarda, G. S., Cui, Y., Hossain, A., Yang, G., James, R. B.
• Format: Article
• Language: English
• Subjects: Absorption cross sections; Abundance; Applied physics; Crystal defects; Crystal growth; Current carriers; Deep level transient spectroscopy; Density; Detectors; Electrical resistivity; Electron mobility; Electron transport; Energy levels; Point defects; Product life cycle; Sensors; Trapping; Traveling Heater Method; Video CD
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4939647

In this research, we assessed the abundance of point defects and their influence on the resistivity, the electron mobility-lifetime (μτe) product, and the electron trapping time in CdTeSe crystals grown under different conditions using the traveling heater method. We used current-deep level transient spectroscopy to determine the traps' energy, their capture cross-section, and their concentration. Further, we used these data to determine the trapping and de-trapping times for the charge carriers. The data show that detectors with a lower concentration of In-dopant have a higher density of A-centers and Cd double vacancies (VCd- -). The high concentrations of VCd- - and A-centers, along with the deep trap at 0.86 eV and low density of 1.1 eV energy traps, are the major cause of the detectors' low resistivity, and most probably, a major contributor to the low μτe product. Our results indicate that the energy levels of point defects in the bandgap, their concentrations, capture cross-sections, and their trapping and de-trapping times play an important role in the detector's performance, especially for devices that rely solely on electron transport.