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Circular polarization in a non-magnetic resonant tunneling device.

Dos Santos LF, Gobato YG, Teodoro MD, Lopez-Richard V, Marques GE, Brasil MJ, Orlita M, Kunc J, Maude DK, Henini M, Airey RJ - Nanoscale Res Lett (2011)

Bottom Line: We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current.The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T).However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects.

View Article: PubMed Central - HTML - PubMed

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

ABSTRACT
We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current. The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T). The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affects the spin polarization of carriers in the QW. However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects.

No MeSH data available.


Related in: MedlinePlus

Schematic band diagram of our device under forward bias, light excitation, and magnetic field parallel to the tunnel current (a). Typical PL emission from contact layers and QW region under 0.52 V and 19 T (b). Current voltage characteristics curves for 0 and 19 T (c,d).
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Figure 1: Schematic band diagram of our device under forward bias, light excitation, and magnetic field parallel to the tunnel current (a). Typical PL emission from contact layers and QW region under 0.52 V and 19 T (b). Current voltage characteristics curves for 0 and 19 T (c,d).

Mentions: Figure 1a shows a schematic band diagram of our device under forward bias voltage and light excitation. Under applied bias, a pseudo-triangular QW is created next to the emitter barrier. Electrons which occupy the quasi-bound states in the triangular QW form a 2DEG. Resonant tunneling can occur between 2DEG states in this triangular well and resonant states in the double-barrier structure (labeled e1). Photogenerated holes can also occupy the quasi-bound states in the triangular QW next to the top contact (collector barrier) and form a 2DHG. Therefore, resonant tunneling can also occur between 2DHG states and hole resonant states (hh1, lh1, and etc.) in the QW.


Circular polarization in a non-magnetic resonant tunneling device.

Dos Santos LF, Gobato YG, Teodoro MD, Lopez-Richard V, Marques GE, Brasil MJ, Orlita M, Kunc J, Maude DK, Henini M, Airey RJ - Nanoscale Res Lett (2011)

Schematic band diagram of our device under forward bias, light excitation, and magnetic field parallel to the tunnel current (a). Typical PL emission from contact layers and QW region under 0.52 V and 19 T (b). Current voltage characteristics curves for 0 and 19 T (c,d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211145&req=5

Figure 1: Schematic band diagram of our device under forward bias, light excitation, and magnetic field parallel to the tunnel current (a). Typical PL emission from contact layers and QW region under 0.52 V and 19 T (b). Current voltage characteristics curves for 0 and 19 T (c,d).
Mentions: Figure 1a shows a schematic band diagram of our device under forward bias voltage and light excitation. Under applied bias, a pseudo-triangular QW is created next to the emitter barrier. Electrons which occupy the quasi-bound states in the triangular QW form a 2DEG. Resonant tunneling can occur between 2DEG states in this triangular well and resonant states in the double-barrier structure (labeled e1). Photogenerated holes can also occupy the quasi-bound states in the triangular QW next to the top contact (collector barrier) and form a 2DHG. Therefore, resonant tunneling can also occur between 2DHG states and hole resonant states (hh1, lh1, and etc.) in the QW.

Bottom Line: We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current.The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T).However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects.

View Article: PubMed Central - HTML - PubMed

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

ABSTRACT
We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current. The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T). The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affects the spin polarization of carriers in the QW. However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects.

No MeSH data available.


Related in: MedlinePlus