Charge Transport and Space-Charge Formation in Cd 1 - x Zn x Te 1 - y Se y Radiation Detectors
- Charles Univ., Prague (Czech Republic)
- Brookhaven National Lab. (BNL), Upton, NY (United States); Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
- Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
The electron- and hole-transport properties in cadmium zinc telluride selenide (CZTS) crystals are studied using a laser-induced transient-current technique with pulsed and dc bias. The internal electric field profile and velocity of surface recombination are determined by Monte Carlo simulations of electron and hole transient currents combined with a numerical solution of the drift-diffusion equation coupled with Poisson’s equation. Electron and hole drift mobilities of μe = 830 cm2/Vs and μh = 40 cm2/Vs, respectively, are determined. We also develop a simple technique for evaluating surface recombination directly from measured current waveforms without the need for numerical simulation. The good quality of the prepared detector at pulsed bias, with electron- and hole-mobility-lifetime products of (μτ)e = 1.9 × 10-3 cm2/V and (μτ)h = 1.4 × 10-4 cm2/V, respectively, are observed. The formation of a positive space charge, originating from hole injection combined with a recombination level, is found. We observe a significant position dependence of the lifetime of electrons and holes in dc bias due to hole injection. The experiment is successfully fitted by a simple model dominated by a single deep recombination level with an energy of Et=EC-0.73eV; concentration of 7.3 × 1011 cm-3; and electron- and hole-capture cross sections of 3.5 × 10-14cm2 and 6.5 × 10-14cm2, respectively.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM)
- Grant/Contract Number:
- 89303321CEM000080
- OSTI ID:
- 1863797
- Report Number(s):
- SRNL-STI-2020-00589; 1234119; 18-12449S; TRN: US2305659
- Journal Information:
- Physical Review Applied, Vol. 15, Issue 5; ISSN 2331-7019
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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