Effect of superstoichiometric components on the spectral and kinetic characteristics of the luminescence of ZnSe crystals with isovalent impurities
Tóm tắt
The spectral and kinetic parameters of the X-ray luminescence of ZnSe crystals doped with Zn, Se, and Te were investigated during the growth process at temperatures in the range 80–500 K, and also after annealing in Zn vapor. ZnSe crystals grown from a stoichiometric mixture, or mixture containing chalcogenide impurities, typically produce the minimum level of afterglow and a rapid rise of X-ray luminescence, as well as a shift of its peak from the infrared region toward shorter wavelengths after annealing in zinc. ZnSe crystals grown from material with excess of Zn have a relatively low X-ray luminescence yield and a substantial level of afterglow. It is assumed that the growth of Te-activated crystals is accompanied by the development of thermally stable complexes of the form V
ZnTeSe that act as radiative recombination centers. The introduction of excess Zn into the initial mixture produces a reduction in the concentration of V
Zn and, hence, in the concentration of radiative recombination centers. It is shown that, for free-electron concentrations n<1018 cm−3, the afterglow time constant τ can be described as a function of n by a model of radiative recombination that involves a single impurity level, whereas for n>1018 cm−3, the time constant decreases with increasing n, which cannot be explained in terms of the simple model. It is suggested that radiative recombination centers of a new type are produced as a result of prolonged annealing in Zn vapor.
Tài liệu tham khảo
A. N. Georgobiani and M. B. Kotlyarevskii, The Pysics of AIIBVI Compounds [in Russian], Nauka, Moscow, 1986, p. 72.
V. D. Ryzhykov, Scintillators in the Form of Semiconducting AIIBVI Compounds: Production, Properties, Applications [in Russian], NIITEKhIM, Moscow, (1989).
V. D. Ryzhykov and E. F. Chaikovskii, Izv. AN SSSR, Ser. fiz. 43, 1150 (1979).
V. D. Ryzhykov, High-efficiency Phodiode-Type Semiconductor Detectors for Monitoring Nuclear Power Stations [in Russian], NIITEKhIM, Khar’kov, 1984.
V. D. Ryzhikov and N. G. Starzhinskii, Ukr. Fiz. Zh. 33, 818 (1988).
V. D. Ryzhikov, Development of Automated Radiation Monotoring for Nuclear Power Stations Using New-generation Phosphor-photodiode Detector Combinations, VNIIM, Kar’kov, 1990, p. 3.
E. Ya. Mellikov, Ya. V. Khiie, P. L. Kukk, and I. V. Karpenko, Izv. AN SSR, Neorg. Mater. 18, 363 (1982).
V. I. Silin, N. G. Starzhinskii, and M. Sh. Fainer, Org. Neorg. Mater. No. 26, 7 (1990).
S. M. Ignatov, V. D. Ryzhikov, V. I. Silin, N. G. Starzhinskii, and Yu. A. Yakovlev, Org. Neorg. Mater. No. 26, 14 (1990).
H. L. Oczkowski, Phys. Status Solidi A 68, 199 (1981).
S. Kishida, K. Matsuura, H. Nagase, H. Mori, F. Takeda, and I. Tsurumi, Phys. Status Solidi A 95, 155 (1986).
B. I. Shklovskii and A. L. Efros, Electronic Properties of Doped Semiconductors [in Russian], Naukov, Moscow, (1979).
J. I. Pankove, Optical Processes in Semiconductors, Dover, N.Y., (1975).
V. B. Sandomirskii, A. G. Zhdan, M. A. Messerer, I. B. Gurlyaev, Ya. A. Pyasta, and A. S. Darevski, Solid-State. Electron. 16, 1097 (1973).
V. D. Ryzhikov, V. I. Silin, and N. G. Starzhinskii, Nucl. Tracks Radiat. Meas., 21, 53 (1993).