Quantum structures in Zn–Se–Te system containing submonolayer quantities of Te
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چکیده
In this paper we show that a multilayer Zn-Se-Te system, grown by molecular beam epitaxy in such a way as to contain sub-monolayer quantities of Te (so-called delta-doped ZnSe:Te), exhibits optical properties consistent with the presence of quantum size centers. We present results of excitation intensity and temperature dependent cw photoluminescence (PL) as well as time-resolved PL measurements that explicitly show that the ensemble of type-II quantum islands is formed in this system. Specifically, for the 2.46–2.51 eV PL we show that (1) its maximum shifts as a cube root of excitation intensity; (2) its fullwidth-at-half-maximum decreases with the temperature while its maximum undergoes a red shift in the temperature interval where the integrated PL intensity stays approximately constant; (3) the PL decay is non-exponential at high excitation intensities and a single exponential decay at low excitation intensities; (4) the PL life-time initially increases with temperature from of 86 ns at T = 15 K to 143 ns at T = 115 K before deceasing due to non-radiative processes.
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تاریخ انتشار 2004