AbstractWe report on a detailed investigation on the temperature-dependent behavior of photoluminescence from molecular beam epitaxy (MBE)-grown chlorine-doped ZnSe epilayers. The overwhelming neutral donor bound exciton (Cl0X) emission at 2.797eV near the band edge with a full-width at half-maximum...
AbstractWe report on a detailed investigation on the temperature-dependent behavior of photoluminescence from molecular beam epitaxy (MBE)-grown chlorine-doped ZnSe epilayers. The overwhelming neutral donor bound exciton (Cl0X) emission at 2.797eV near the band edge with a full-width at half-maximum (FWHM) of ∼13meV reveals the high crystalline quality of the samples used. In our experiments, the quick quenching of the Cl0X line above 200K is mainly due to the presence of a nonradiative center with a thermal activation energy of ∼90meV. The same activation energy and similar quenching tendency of the Cl0X line and the I3 line at 2.713eV indicate that they originate from the same physical mechanism. We demonstrate for the first time that the dominant decrease of the integrated intensity of the I3 line is due to the thermal excitation of the “I3 center”-bound excitons to its free exciton states, leaving the “I3 centers” as efficient nonradiative centers. The optical performance of ZnSe materials is expected to be greatly improved if the density of the “I3 center” can be controlled. The decrease in the luminescence intensity at moderately low temperature (30–200K) of the Cl0X line is due to the thermal activation of neutral-donor-bound excitons (Cl0X) to free excitons.
AbstractWe report on a detailed investigation on the temperature-dependent behavior of photoluminescence from molecular beam epitaxy (MBE)-grown chlorine-doped ZnSe epilayers. The overwhelming neutral donor bound exciton (Cl0X) emission at 2.797eV near the band edge with a full-width at half-maximum (FWHM) of ∼13meV reveals the high crystalline quality of the samples used. In our experiments, the quick quenching of the Cl0X line above 200K is mainly due to the presence of a nonradiative center with a thermal activation energy of ∼90meV. The same activation energy and similar quenching tendency of the Cl0X line and the I3 line at 2.713eV indicate that they originate from the same physical mechanism. We demonstrate for the first time that the dominant decrease of the integrated intensity of the I3 line is due to the thermal excitation of the “I3 center”-bound excitons to its free exciton states, leaving the “I3 centers” as efficient nonradiative centers. The optical performance of ZnSe materials is expected to be greatly improved if the density of the “I3 center” can be controlled. The decrease in the luminescence intensity at moderately low temperature (30–200K) of the Cl0X line is due to the thermal activation of neutral-donor-bound excitons (Cl0X) to free excitons.
S.Z. Wang, Design and growth of II-VI materials for blue/green laser diodes, Shanghai Institute of Technical Physics, Academia Sinica, Shanghai, 1997, p. 10, and references therein.
J. Chin. Electron. Microsc. Soc. Wang 16 385 1997
J. Crystal Growth Ohkawa 117 375 1992 10.1016/0022-0248(92)90779-I
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