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

Liang, Baolai, Huffaker, Diana, 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 Mar 2019 11:15

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