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Spin effects in InAs self-assembled quantum dots.

Dos Santos EC, Gobato YG, Brasil MJ, Taylor DA, Henini M - Nanoscale Res Lett (2011)

Bottom Line: We have studied the polarized resolved photoluminescence in an n-type resonant tunneling diode (RTD) of GaAs/AlGaAs which incorporates a layer of InAs self-assembled quantum dots (QDs) in the center of a GaAs quantum well (QW).We have observed that the QD circular polarization degree depends on applied voltage and light intensity.Our results are explained in terms of the tunneling of minority carriers into the QW, carrier capture by InAs QDs and bias-controlled density of holes in the QW.

View Article: PubMed Central - HTML - PubMed

Affiliation: Physics Department, Federal University of São Carlos, São Carlos, Brazil. yara@df.ufscar.br.

ABSTRACT
We have studied the polarized resolved photoluminescence in an n-type resonant tunneling diode (RTD) of GaAs/AlGaAs which incorporates a layer of InAs self-assembled quantum dots (QDs) in the center of a GaAs quantum well (QW). We have observed that the QD circular polarization degree depends on applied voltage and light intensity. Our results are explained in terms of the tunneling of minority carriers into the QW, carrier capture by InAs QDs and bias-controlled density of holes in the QW.

No MeSH data available.


Related in: MedlinePlus

Schematic potential profile and carrier dynamics in the RTD.
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Figure 1: Schematic potential profile and carrier dynamics in the RTD.

Mentions: Figure 1 shows the schematic potential profile and carrier dynamics in our device. Under applied bias voltage, electrons are injected from the GaAs emitter layer into the QW region. Resonant tunneling condition is obtained when the energy of carriers is equal to the energy of confined states in the QW. Under laser excitation, photogenerated holes tunnel through the QW and can be captured by the QDs and eventually recombine radiatively. Carrier capture into QDs occurs within typical times of about 1 ps which is much shorter than the characteristic dwell times of electrons and holes that are tunneling resonantly into the QW. Due to this fast carrier capture process, the QD photoluminescence will be very sensitive to the resonant tunneling condition and consequently to the applied bias voltage.


Spin effects in InAs self-assembled quantum dots.

Dos Santos EC, Gobato YG, Brasil MJ, Taylor DA, Henini M - Nanoscale Res Lett (2011)

Schematic potential profile and carrier dynamics in the RTD.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211160&req=5

Figure 1: Schematic potential profile and carrier dynamics in the RTD.
Mentions: Figure 1 shows the schematic potential profile and carrier dynamics in our device. Under applied bias voltage, electrons are injected from the GaAs emitter layer into the QW region. Resonant tunneling condition is obtained when the energy of carriers is equal to the energy of confined states in the QW. Under laser excitation, photogenerated holes tunnel through the QW and can be captured by the QDs and eventually recombine radiatively. Carrier capture into QDs occurs within typical times of about 1 ps which is much shorter than the characteristic dwell times of electrons and holes that are tunneling resonantly into the QW. Due to this fast carrier capture process, the QD photoluminescence will be very sensitive to the resonant tunneling condition and consequently to the applied bias voltage.

Bottom Line: We have studied the polarized resolved photoluminescence in an n-type resonant tunneling diode (RTD) of GaAs/AlGaAs which incorporates a layer of InAs self-assembled quantum dots (QDs) in the center of a GaAs quantum well (QW).We have observed that the QD circular polarization degree depends on applied voltage and light intensity.Our results are explained in terms of the tunneling of minority carriers into the QW, carrier capture by InAs QDs and bias-controlled density of holes in the QW.

View Article: PubMed Central - HTML - PubMed

Affiliation: Physics Department, Federal University of São Carlos, São Carlos, Brazil. yara@df.ufscar.br.

ABSTRACT
We have studied the polarized resolved photoluminescence in an n-type resonant tunneling diode (RTD) of GaAs/AlGaAs which incorporates a layer of InAs self-assembled quantum dots (QDs) in the center of a GaAs quantum well (QW). We have observed that the QD circular polarization degree depends on applied voltage and light intensity. Our results are explained in terms of the tunneling of minority carriers into the QW, carrier capture by InAs QDs and bias-controlled density of holes in the QW.

No MeSH data available.


Related in: MedlinePlus