Zhuhong Zheng

Ultraviolet photoluminescence from 3C-SiC nanorods

An intensive sharp photoluminescence at 3.3eV is observed from single-crystal 3C-SiC nanorods. Structural characterization reveals that the nanorods contain a fairly large amount of threefold stacking faults. We tentatively attribute the emission to these stalking faults, which structurally resemble 6H-SiC nano-layers of 1.5nm embedded in a 3C-SiC matrix. The emission mechanism is discussed in terms of spontaneous polarization at the stacking faults.

Narrow luminescence lines from self-assembled CdSe quantum dots at room temperature

Narrow luminescence lines from self-assembled CdSe quantum dots (QDs) are studied at room temperature by using time-resolved photoluminescence spectroscopy. The narrowest line of the luminescence has a full width at half maximum of 2.1 meV at room temperature. The narrow luminescence lines are mainly the contribution of CdSe QDs with a longer recombination lifetime to the luminescence.

ZnBeSe epitaxy layers grown by photo-assisted metalorganic chemical vapor deposition

Low-temperature growth of ZnBeSe epilayer on GaAs substrates has been carried out at low-pressure (LP) by photo-assisted metalorganic chemical vapor deposition (MOCVD) using a ultrahigh-pressure mercury lamp as a light source. High-temperature growth of ZnBeSe has been also achieved by LP-MOCVD without light irradiation. It was found that the full-width at half-maximum of the diffraction peak of ZnBeSe epilayer increased with increasing irradiation intensity and growth temperature. The intensity of the emission band related to the excitons was obviously reduced due to poor quality of epilayer at high irradiation intensity and the deep-level emission band was predominant in the spectra.

Temperature-dependent exciton recombination in asymmetrical ZnCdSe/ZnSe double quantum wells

Temperature-dependent exciton recombination in asymmetrical ZnCdSe/ZnSe double quantum wells is studied by recording photoluminescence spectra and photoluminescence decay spectra. The exciton tunnelling from the wide well to the narrow well and the thermal dissociation of excitons are two factors that influence the exciton recombination in this structure. In the narrow well, both of the two processes decrease the emission intensity, whereas, in the wide well, these two processes have contrary influences on the exciton density. The change of the emission intensity depends on which is the stronger one.