Fast electron spin resonance controlled manipulation of spin injection into quantum dots

Merz, Andreas; Siller, Jan; Schittny, Robert; Krämmer, Christoph; Kalt, H.; Hetterich, M.

doi:10.1063/1.4884016

Cited by 4 publications

(2 citation statements)

References 18 publications

(18 reference statements)

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“…Here a key issue is the injection in the so-called tunnel regime. This allows circumventing the conductivity mismatch problem between the ferromagnetic (FM) electrode and the semiconductor by introducing MgO tunnel barriers. ,, Optically active semiconductor nanostructures such as quantum dots are excellent model systems for various applications: , compact sources (spin LEDs, − spin lasers) of polarized light (for information science, detection of chirality in life science, three-dimensional (3D) screens) based on p-i-n junctions, as well as single quantum bits for quantum computation…”

Section: Polarization-resolved Electroluminescence Of a Quantum Dot E...mentioning

confidence: 99%

Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field

et al. 2018

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The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to 35% at zero applied magnetic field. The injection of spin-polarized electrons is achieved by combining ultrathin CoFeB electrodes on top of a spin-LED device with p-type InGaAs quantum dots in the active region. We measure an Overhauser shift of several microelectronvolts at zero magnetic field for the positively charged exciton (trion X) EL emission, which changes sign as we reverse the injected electron spin orientation. This is a signature of dynamic polarization of the nuclear spins in the quantum dot induced by the hyperfine interaction with the electrically injected electron spin. This study paves the way for electrical control of nuclear spin polarization in a single quantum dot without any external magnetic field.

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Section: Polarization-resolved Electroluminescence Of a Quantum Dot E...mentioning

confidence: 99%

Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field

et al. 2018

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“…[3][4][5][6] The interest in these nanostructures is due to their unique electrical, optical, and transport characteristics as compared with conventional materials, including two-and one-dimensional nanomaterials. [7][8][9][10][11][12][13] The concept of QDQWs was brought by Esaki and Tsu, 14 who established the idea of super-lattices and quantum wells (QWs) in semiconductor heterostructures. Following in their footsteps, it was found that the electron levels and resonance quantum tunnel effect of the QWs that were buried in super-lattice structures have the potential for widespread use in the fields of advanced generation photoelectronic and microelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Carrier transport in quantum dot quantum well microstructures of the self-assembled CdTe/CdS/ligand core–shell system

Shan

Zhu

et al. 2015

Nanoscale

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The study on the quantum dot quantum well (QDQW) microstructure modified by choosing different ligands containing a sulfhydryl group is of significance because it enables one to regulate photoexcited free charge carriers' (FCCs') transport behaviours in high-quality CdTe/ligand QDs via a self-assembled way. The photoelectron characteristics of ligand-capped CdTe nanoparticles were probed by a combination of surface photovoltaic (SPV) and photoacoustic technologies, supplemented by a computer simulation method of the CASTEP module. The experiment reveals that the D-value ΔEWi obtained by the associated two parameters of the SPV spectroscopy was closely related to the quantum confinement energy in the self-assembled CdTe/CdS/ligand core-shell system. In the paper the D-value was termed the depth of QWs, which were buried in the space charge regions located in the graded-band-gap and on either side of the shell-CdS. Obvious resonance quantum tunnelling may occur in the energy band structure with deep QWs on using certain ligands, resulting in an extended diffusion length of the FCCs on illumination of the photon energy hν ≥ Eg, core-CdTe, and in a strong SPV response at a specific wavelength region. In addition, the carrier-longitudinal optical phonon interaction is the reciprocal of the carriers' lifetime. The d-frontier orbital in the graded-band-gap plays an important role in both the microstructure and the resonance quantum tunnelling of the QDQW system according to the CASTEP calculations.

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Photogenerated carriers enhancement in Cu-doped ZnSe/ZnS/L-cys self-assembled core-shell quantum dots

Cui

Ren

et al. 2016

Journal of Applied Physics

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The photoelectron characteristics and nano-doping mechanism of Cu-doped ZnSe/ZnS/L-cys self-assembled core-shell quantum dots (QDs) are studied by surface photovoltaic (SPV) and photoacoustic (PA) techniques, XRD, HRTEM, FT-IR, UV-VIS adsorption, and Laser Raman spectra. The results suggest that the doped copper element prefers to locate at the Zn atom-vacancy of the (111) face of the QDs in the Cu2+ ion form. The defect-state levels are referred to the shallow accepter levels, leading to an obvious quantum confinement effect and a weakened n-type surface photovoltaic characteristic in the Cu-doped QDs. The quantum confinement effect strongly depends on the depth of the quantum well that is buried in the space charge region located in the graded-band-gap and at the side of the core-ZnSe. These electron structures are responsible for the increased lifetime and diffusion length of photogenerated free charge carriers, which significantly enhance the intensity of SPV response, enlarge the range of SPV response, and weaken the PA signals that are closely related to non-radiation deexcitation processes.

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Fast electron spin resonance controlled manipulation of spin injection into quantum dots

Cited by 4 publications

References 18 publications

Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field

Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field

Carrier transport in quantum dot quantum well microstructures of the self-assembled CdTe/CdS/ligand core–shell system

Photogenerated carriers enhancement in Cu-doped ZnSe/ZnS/L-cys self-assembled core-shell quantum dots

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