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Type-II GaSb/InAlAs quantum dots grown on InP (001) substrate by droplet epitaxy (Conference Presentation)

Liang, Baolai, Huffaker, Diana ORCID:, Mazur, Yuriy, Ware, Morgan, Salamo, Gregory, Yuan, Qing, Wang, Ying, Li, Xiaoli, Wang, Shufang and Fu, Guangsheng 2019. Type-II GaSb/InAlAs quantum dots grown on InP (001) substrate by droplet epitaxy (Conference Presentation). Presented at: SPIE OPTO, San Francisco, CA, USA, 2-7 February 2019. Published in: Huffaker, Diana L. ed. Proceedings Volume 10929, Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XVI. Society of Photo-Optical Instrumentation Engineers (SPIE), 109290H. 10.1117/12.2509207

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The GaSb quantum dots (QDs) with type II band alignment have attracted great attention recently. They are predicted to be optimizing active region materials for achieving high efficient intermediate-band solar cells and for obtaining ultra-long storage time for memory cells. In this research, GaSb QDs sandwiched inside InAlAs matrix lattice-matched to InP (001) substrate have been obtained via droplet epitaxy. The droplet epitaxy enable us to achieve low density (~2.6 x 10^9/cm^2) and large size (average height ~6.5nm) for the QDs while the lattice mismatch between the GaSb and InAlAs matrix is only ~4%. PL measurements reveal a type-II band alignment for these GaSb/InAlAs/InP QDs. The PL peak energy of QDs shows a blue-shift of >100 meV when the laser intensity increases by six orders of magnitude. Time-resolved PL measurements further confirm the type-II band alignment for the QDs by showing a maximum carrier lifetime of ~4.5 ns. The abnormal dependence of peak energy of QD PL band on the temperature in together with the special PL decay curve indicate that these GaSb/InAlAs QDs likely have different physics mechanism from common GaSb/GaAs type-II QDs. This study provide useful information for understanding the band structure and carrier dynamics of the GaSb/InAlAs QDs grown on InP surface.

Item Type: Conference or Workshop Item (Paper)
Date Type: Published Online
Status: Published
Schools: Physics and Astronomy
Publisher: Society of Photo-Optical Instrumentation Engineers (SPIE)
Date of First Compliant Deposit: 22 March 2019
Date of Acceptance: 4 March 2019
Last Modified: 25 Oct 2022 13:54

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