Browsing by Author "Tanaka, Tooru"

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Carrier dynamics in dilute II-VI oxide highly mismatched alloys
(2014)
Lin, Yan-Cheng
;
Chou, Wu-Ching
;
Chyi, Jen-Inn
;
Tanaka, Tooru
;
電子物理學系
This study explores comprehensively the carrier dynamics in ZnSeO and ZnTeO using photoluminescence (PL) and time-resolved PL spectroscopy. As the O concentration increases, the PL emissions shift toward lower energies. Additionally, the PL lifetime increases with increasing O contents and the decay curves exhibit complex behavior. In the case of ZnSeO, the mechanism of carrier recombination undergoes a complicated change from trapped to free excitons with the increase in temperature. The incorporation of O in ZnTe generates a wide distribution of electron localization below the energy of the E- conduction subband, and these cause broad PL emission and serve as another intermediate band. Electrons in both the E+ and the E- conduction subbands favor rapid relaxation to low energy states. Moreover, temperature-independent long carrier lifetimes (> 130.0 ns) that are induced by localized electrons increase with O concentration.
Recombination dynamics and carrier lifetimes in highly mismatched ZnTeO alloys
(2013-12-23)
Lin, Yan-Cheng
;
Tasi, Ming-Jui
;
Chou, Wu-Ching
;
Chang, Wen-Hao
;
Chen, Wei-Kuo
This study investigates the recombination dynamics in highly mismatched ZnTeO alloys using time-resolved photoluminescence (PL) spectroscopy. The large PL energy redshift with increasing O content and the disappearance of the ZnTe emission verify the O-induced conduction band anticrossing effect. The incorporation of O generates electron localization below the E_ conduction subband tail, which provide additional optical transitions and cause complex recombination mechanisms. Photoexcited free electrons in both the E+ and the E- conduction subbands favor rapid relaxation to low energy states. Additionally, temperature-independent long carrier lifetimes (>130.0 ns) that are induced by localized electrons increase with O concentration. (C) 2013 AIP Publishing LLC.