Relaxation-induced lattice misfits and their effects on the emission properties of InAs quantum dots

Chen, Jenn–Fang; Wang, Y. Z.; Chiang, Chen‐Yu; Hsiao, R. S.; Wu, Yue; Chang, Li; Wang, J. S.; W., T.; Y., J.

doi:10.1088/0957-4484/18/35/355401

Cited by 10 publications

(18 citation statements)

References 28 publications

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“…[1] In addition, the strain relaxation induces a misfit defect at the bottom of the InAs QDs. This defect has been confirmed by transmission electron microscopy (TEM) images [2,3]. The misfit defect also enhances the confinement of the QDs.…”

Section: Sample Fabrication and Propertiesmentioning

confidence: 69%

The reading operation of quantum dot memory devices using photocurrent detection in strain relaxation InAs quantum dots

Wang

Lin

Pan

et al. 2014

Extended Abstracts of the 2014 International Conference on Solid State Devices and Materials

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We demonstrate the memory devices using the combination of the two devices, the GaAs Schottky diode and the InAs quantum dots (QDs) embedded in GaAs matrix. The photocurrent generated from the Schottky diode can be suppressed by the charged InAs QDs device behind. And further, the photocurrent can be controlled by the feedback between the two devices. The equivalent RC circuit model is provided in this paper, and the effective capacitance of the InAs QDs is obtained as about 0.1μF. Besides, it is also proved that the strain relaxation QDs with misfit defect is more suitable to be fabricated as the quantum dot memory devices than the perfect non-relaxed QDs.

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Section: Sample Fabrication and Propertiesmentioning

confidence: 69%

The reading operation of quantum dot memory devices using photocurrent detection in strain relaxation InAs quantum dots

Wang

Lin

Pan

et al. 2014

Extended Abstracts of the 2014 International Conference on Solid State Devices and Materials

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“…This emission time is very short, as indicated by 'InAs QDs' in figure 3. The Ninduced defect state (indicated by a dashed line) can suppress the tunneling emission, presumably by inducing additional carrier depletion [11] and increasing the tunneling width (the detailed band structure is not shown). Electrons escaping out of the GS have to emit to a state near the GaAs CB, leading to a significant emission energy increase from 0.058 to 0.15 eV and several orders of magnitude increase in the emission time.…”

Section: Resultsmentioning

confidence: 99%

Electron emissions in InAs quantum dots containing a nitrogen incorporation induced defect state: the influence of thermal annealing

Chen

Yu²,

Yang³

2008

Nanotechnology

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With the incorporation of nitrogen (N) into InAs quantum dots (QDs), the carrier distribution near the QD displays electron emissions from a localized N-induced defect state at 0.34 eV and a weak emission at 0.15 eV from the QD. This defect state causes drastic carrier depletion in the neighboring GaAs bottom layer near the QD, which can effectively suppress tunneling emission for the QD excited states. As a result, electrons escape from the QD ground state through thermal emission to near the GaAs conduction band, rather than through thermal emission to the QD first excited state and a subsequent tunneling to the GaAs conduction band, as observed in InAs QDs without N incorporation. Thermal annealing can weaken the defect emission and enhance the QD emission, suggesting a removal of the defect state and a recovery of carriers in the QD. Increasing annealing temperature can significantly decrease the emission time and energy of the QD emission, which is explained by a weakening of tunneling suppression due to the removal of the defect state.

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“…This defect state is associated with relaxationinduced lattice misfits observed by Fourier transformed cross-sectional TEM. 25 Annealing at 650°C does not much affect the concentration and emission parameters of this defect state. We had investigated the DLTS spectra by varying filling pulse duration time and found that the amplitude of the defect state saturated when filling pulse duration time was increased to about 1 ms.…”

Section: A Electron Distribution In the Qdsmentioning

confidence: 91%

Influence of thermal annealing on the electron emission of InAs quantum dots containing a misfit defect state

Chen

Yang

Hsu

et al. 2009

Journal of Applied Physics

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We have investigated the effect of postgrowth thermal annealing on the electron emission from InAs quantum dots ͑QDs͒ containing a misfit-related defect state induced by strain relaxation. Additional carrier depletion in the GaAs bottom layer near the QD, caused by the defect state, can effectively suppress electron tunneling from the QD, leading to the observation of a thermal emission from the QD electron ground state to the GaAs conduction band with a large emission energy of 213 meV, in contrast to defect-free nonrelaxed QDs in which an emission of 58 meV from the QD electron ground state to first excited state is observed. The emission energy is reduced to 193 meV and to 164 meV after annealing at 650 and 700°C for 1 min, respectively. This emission energy reduction is correlated with the photoluminescence blueshift which is attributed to the interdiffusion of atoms across the QD interface. The electron emission from the QD first excited and ground states is found to be a thermal emission at high temperatures and a tunneling emission at low temperatures. The tunneling energy barrier is found to be comparable to the thermal emission energy, supporting a thermal emission to the GaAs conduction band. This study illustrates a significant effect of a defect state on the electron-emission process in the QDs, suggesting the possibility of modifying the electron emission time of the QDs by purposely introducing a deep defect state.

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Relaxation-induced lattice misfits and their effects on the emission properties of InAs quantum dots

Cited by 10 publications

References 28 publications

The reading operation of quantum dot memory devices using photocurrent detection in strain relaxation InAs quantum dots

The reading operation of quantum dot memory devices using photocurrent detection in strain relaxation InAs quantum dots

Electron emissions in InAs quantum dots containing a nitrogen incorporation induced defect state: the influence of thermal annealing

Influence of thermal annealing on the electron emission of InAs quantum dots containing a misfit defect state

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