Reversible conductivity control and quantitative identification of compensating defects in ZnSe bulk crystals

Donor compensation by associates of donor impurities and cation vacancies is investigated in vapor grown ZnSe : I and Al diffused melt grown bulk crystals. Both the (I SeV Zn) and the (Al ZnV Zn) A-centers could be identified by electron paramagnetic resonance (EPR) spectroscopy. The concentrations...

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Bibliographic Details
Published in:Journal of crystal growth 2000-06, Vol.214, p.988-992
Main Authors: Prokesch, M, Irmscher, K, Gebauer, J, Krause-Rehberg, R
Format: Article
Language:English
Subjects:
Absorption
Doping
Electron paramagnetic resonance
Positron annihilation
Self-compensation
ZnSe bulk crystals
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Summary:Donor compensation by associates of donor impurities and cation vacancies is investigated in vapor grown ZnSe : I and Al diffused melt grown bulk crystals. Both the (I SeV Zn) and the (Al ZnV Zn) A-centers could be identified by electron paramagnetic resonance (EPR) spectroscopy. The concentrations of the compensating defects can be reversibly changed by vapor-phase equilibration and a reproducible adjustment of room temperature (RT) carrier concentrations n e up to 1.4×10 18 cm −3 (ZnSe : I) and 2.7×10 18 cm −3 (ZnSe : Al) is possible. The results are explained in terms of a defect chemical model. The supposed high concentrations of one type of vacancy associated defects are confirmed using positron annihilation (PA). Lowered compensation leads to an increase of carrier mobility μ e with increasing n e. In low doped systems mobilities of 500 cm 2/Vs can be obtained. A similarly drastic shift of the absorption edge to lower photon energies is observed for both I- and Al-doped crystals.
ISSN:0022-0248
1873-5002
DOI:10.1016/S0022-0248(00)00232-3