Hole migration and optically induced charge depletion in GaSb/GaAs wetting layers and quantum rings
We present the results of photoluminescence (PL) measurements on a type-II GaSb/GaAs quantum dot/ring sample as a function of temperature (2 to 400 K) and over six orders of magnitude of incident laser excitation power. Optically induced charge depletion (OICD) was seen in both the wetting layer (...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
American Physical Society
2013
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| Online Access: | http://psasir.upm.edu.my/id/eprint/30304/1/Hole%20migration%20and%20optically%20induced%20charge%20depletion%20in%20GaSb.pdf http://psasir.upm.edu.my/id/eprint/30304/ |
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| Summary: | We present the results of photoluminescence (PL) measurements on a type-II GaSb/GaAs quantum dot/ring
sample as a function of temperature (2 to 400 K) and over six orders of magnitude of incident laser excitation
power. Optically induced charge depletion (OICD) was seen in both the wetting layer (WL) and quantum
dots/rings but with remarkably different temperature dependent behavior. Holes originating from background
acceptors migrate out of the WL as the sample temperature is raised to 30 K, while the onset of a blueshift in the
PL from quantum rings, signaling their thermally induced charging with holes, is only observed at temperatures
above 300 K. The presence of dark dots as a hidden reservoir for acceptor holes at the intermediate temperatures is
proposed to explain this anomalous behavior. Due to the deep localization potential of GaSb/GaAs, thermalization
of acceptor holes between dark dots and bright rings only occurs above room temperature. A rate equation model
is presented which successfully replicates the main features of OICD observed here and in previous reports |
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