標題: | Study of extending carrier lifetime in ZnTe quantum dots coupled with ZnCdSe quantum well |
作者: | Fan, W. C. Chou, W. C. Lee, J. D. Lee, Ling Nguyen Dang Phu Luc Huy Hoang 電子物理學系 Department of Electrophysics |
關鍵字: | Molecular beam epitaxy;Quantum dots;Time resolved photoluminescence;Recombination dynamics |
公開日期: | 1-三月-2018 |
摘要: | We demonstrated the growth of a self-assembled type-II ZnTe/ZnSe quantum dot (QD) structure coupled with a type-I Zn0.88Cd0.12Se/ZnSe quantum well (QW) on the (001) GaAs substrate by molecular beam epitaxy (MBE). As the spacer thickness is less than 2 nm, the carrier lifetime increasing from 20 ns to nearly 200 ns was successfully achieved. By utilizing the time-resolved photoluminescence (TRPL) and PL with different excitation power, we identify the PL emission from the coupled QDs consisting of two recombination mechanisms. One is the recombination between electrons in ZnSe barrier and holes confined within ZnTe QDs, and the other is between electrons confined in Zn0.88Cd0.12Se QW and holes confined within ZnTe QDs. According to the band diagram and power-dependent PL, both of the two recombinations reveal the type-II transition. In addition, the second recombination mechanism dominates the whole carrier recombination as the spacer thickness is less than 2 nm. A significant extension of carrier lifetime by increasing the electron and hole separation is illustrated in a type-II ZnTe/ZnSe QD structure coupling with a type-I ZnCdSe/ZnSe QW. Current sample structure could be used to increase the quantum efficient of solar cell based on the II-VI compound semiconductors. |
URI: | http://dx.doi.org/10.1016/j.physb.2017.04.024 http://hdl.handle.net/11536/144571 |
ISSN: | 0921-4526 |
DOI: | 10.1016/j.physb.2017.04.024 |
期刊: | PHYSICA B-CONDENSED MATTER |
Volume: | 532 |
起始頁: | 195 |
結束頁: | 199 |
顯示於類別: | 期刊論文 |