Temperature dependence of the dynamics of optical spin injection in self-assembled InGaAs quantum dots

Kiba, Takayuki; Yang, Xiaojie; Yamamura, Takuya; Kuno, Yuki; Subagyo, Agus; Sueoka, Kazuhisa; Murayama, Akihiro

doi:10.1063/1.4819208

Cited by 27 publications

(47 citation statements)

References 28 publications

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“…The best-fitted rateequation calculations are shown by solid lines, with specific details of the rate-equation analysis described in a previous paper. 5 The rate-equation model is schematically illustrated in Fig. 5(a), where parameters responsible for the injection of spin-polarized excitons and subsequent relaxation are included.…”

Section: Resultsmentioning

confidence: 99%

“…5 The exception was the substrate temperature during QD growth (T s ), which for the purposes of this study was varied from 470 to 520 C. A GaAs barrier was then applied to the QD layer, onto which an additional layer of QDs was grown to allow observation of the dot structure by atomic force microscopy (AFM) and high-resolution scanning electron microscopy (SEM). Cross-sectional transmission electron microscopy (TEM) was also used for observation of the layered sample structure.…”

Section: Methodsmentioning

confidence: 99%

“…Circularly polarized time-resolved PL spectra were obtained using a previously described method, 5 wherein optical spin injection was achieved by resonantly exciting the bottom of the energy-band gap of the GaAs barrier using circularly polarized light pulses. The spin-polarized electron-hole pairs were subsequently generated in the barrier in accordance with the optical spin orientation rule, 18 which takes into account the spin states of the carriers and the circular polarization of the excitation light.…”

Section: Methodsmentioning

confidence: 99%

“…2,3 However, there is still a need to take a closer look at the spin states during the injection of spin-polarized carriers or excitons, i.e., spin injection from a layered semiconductor barrier into a QD. [5][6][7][8][9][10] Such spin injection has the potential to provide the key to applying the spin states of QDs to spin-functional optical devices, as one would need to inject spin-polarized carriers from electrodes into QDs to achieve a practical device structure. Indeed, spin-polarized light emitting diodes and lasers based on QDs have been discussed; [11][12][13][14] however, spin injection is recognized as being much more difficult than spin-independent carrier injection due to the relative instability of the spin states in layered semiconductors, which allows them to easily relax during the injection process.…”

Section: Introductionmentioning

confidence: 99%

“…5 This results in a decrease in the total spin polarization at excited states in the QDs due to the subsequent accumulation of minority spins, during the injection of majority spins is blocked. The problem which one has to consider next, however, is precisely what kind of QD system is the most appropriate for achieving efficient spin injection while also maintaining high spin polarization, even in the case of strong excitation or pumping.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Growth-temperature dependence of optical spin-injection dynamics in self-assembled InGaAs quantum dots

Yamamura

Kiba

Yang

et al. 2014

Journal of Applied Physics

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Articles you may be interested inThe growth-temperature dependence of the optical spin-injection dynamics in self-assembled quantum dots (QDs) of In 0.5 Ga 0.5 As was studied by increasing the sheet density of the dots from 2 Â 10 10 to 7 Â 10 10 cm À2 and reducing their size through a decrease in growth temperature from 500 to 470 C. The circularly polarized transient photoluminescence (PL) of the resulting QD ensembles was analyzed after optical excitation of spin-polarized carriers in GaAs barriers by using rate equations that take into account spin-injection dynamics such as spin-injection time, spin relaxation during injection, spin-dependent state-filling, and subsequent spin relaxation. The excitation-power dependence of the transient circular polarization of PL in the QDs, which is sensitive to the state-filling effect, was also examined. It was found that a systematic increase occurs in the degree of circular polarization of PL with decreasing growth temperature, which reflects the transient polarization of exciton spin after spin injection. This is attributed to strong suppression of the filling effect for the majority-spin states as the dot-density of the QDs increases.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Growth-temperature dependence of optical spin-injection dynamics in self-assembled InGaAs quantum dots

Yamamura

Kiba

Yang

et al. 2014

Journal of Applied Physics

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On the control of optical spin injection by tuning the band gap offset in magnetic/non-magnetic hybrid structure

Ghali

2014

Optics & Laser Technology

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Electric-Field-Effect Spin Switching with an Enhanced Number of Highly Polarized Electron and Photon Spins Using p-Doped Semiconductor Quantum Dots

et al. 2021

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Electric-field-effect spin switching with an enhanced number of highly polarized electron and photon spins has been demonstrated using p-doped semiconductor quantum dots (QDs). Remote p-doping in InGaAs QDs tunnel-coupled with an InGaAs quantum well (QW) significantly increased the circularly polarized, thus electron-spin-polarized, photoluminescence intensity, depending on the electric-field-induced electron spin injection from the QW as a spin reservoir into the QDs. The spin polarity and polarization degree during this spin injection can be controlled by the direction and the strength of the electric field, where the spin direction can be reversed by excess electron spin injection into the QDs via spin scattering at the QD excited states. We found that the maximum degrees of both parallel and antiparallel spin polarization to the initial spin direction in the QW can be enhanced by p-doping. The doped holes without spin polarization can effectively contribute to this electric-field-effect spin switching after the initial electron spin injection selectively removes the parallel hole spins. The optimized p-doping induces fast spin reversals at the QD excited states with a moderate electric-field application, resulting in an efficient electric-field-driven antiparallel spin injection into the QD ground state. Further excess hole doping prevents this efficient spin reversal due to multiple electron−hole spin scattering, in addition to a spin-state filling effect at the QD excited states, during the spin injection from the QW into the QDs.

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Temperature dependence of the dynamics of optical spin injection in self-assembled InGaAs quantum dots

Cited by 27 publications

References 28 publications

Growth-temperature dependence of optical spin-injection dynamics in self-assembled InGaAs quantum dots

Growth-temperature dependence of optical spin-injection dynamics in self-assembled InGaAs quantum dots

On the control of optical spin injection by tuning the band gap offset in magnetic/non-magnetic hybrid structure

Electric-Field-Effect Spin Switching with an Enhanced Number of Highly Polarized Electron and Photon Spins Using p-Doped Semiconductor Quantum Dots

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