Electroluminescence of superatom-like Ge-core/Si-shell quantum dots by alternate field-effect-induced carrier injection

Makihara, Katsunori; Ikeda, Mitsuhisa; Fujimura, Nobuyuki; Yamada, Kazuo; Ohta, Akio; Miyazaki, Seiichi

doi:10.7567/apex.11.011305

Cited by 14 publications

(11 citation statements)

References 21 publications

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“…We have focused on CVD formation and characterization of Si-QDs with Ge-core, and reported room temperature photoluminescence (PL) properties attributable to type II energy-band alignment between the Ge-core and the Si-shell [10][11][12][13][14][15]. In addition, we have also demonstrated stable electroluminescence in the near-infrared region from light-emitting-devices having a 3-fold stacked Si-QDs with Ge core with an areal density of ~2.0×10 11 cm −2 under pulsed bias applications [16]. One of the possible ways to enhance the radiative recombination rate and improve the light emission efficiency is to reduce non-radiative centers and increase carrier density with impurity doping into the QDs.…”

Section: Introductionmentioning

confidence: 83%

Characterization of Light Emission Properties of Impurity Doped Ge/Si Core–Shell Quantum Dots

Miyazaki¹,

Imai²,

Makihara³

2022

ECS Trans.

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We have fabricated valency-controlled Si-QDs with Ge-core with an areal density as high as ~1011 cm-2 on ultrathin SiO2 and studied the effect of phosphorus- and boron-doping on Ge-core from their PL properties. During the Ge deposition, delta doping of phosphorus or boron atoms in QDs was carried out by pulse injection using 1% PH3 or B2H6 diluted with He, respectively. No changes in dot size and density with either P- or B-doping were confirmed by AFM topographic images. Under photoexcitation of undoped QDs with a 976-nm line from a semiconductor laser, broad PL spectra consisting of four Gaussian components originating from radiative recombination through quantized states in QDs were observed in the energy range from 0.62 to 0.85 eV without impurity doping even at room temperature. In the doped QDs, relatively-narrow components peaked at ~0.68 eV and ~0.64eV were observed with P-doping and with B-doping to Ge-core, respectively, in addition to the four components seen in undoped QDs. It is interesting noted that, with an increase in B2H6 pulse injection from 1 to 4 times, the integrated PL intensity was enhanced by a factor of 1.4 to 2.4 compared to that of the undoped QDs while no significant change in spectral shape was observable. This can be interpreted in terms of an increase in the number of holes with B-doping to the Ge core since the carrier recombination rates is proportional to the product of the number of electrons and holes confined in QD under weak photoexcitation.

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Section: Introductionmentioning

confidence: 83%

Characterization of Light Emission Properties of Impurity Doped Ge/Si Core–Shell Quantum Dots

Miyazaki¹,

Imai²,

Makihara³

2022

ECS Trans.

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“…Si-based Ge quantum dots (Ge/Si QDs) exhibited many novel photoelectric properties due to their quantum confinement effect and compatibility with Si-based circuits, which have a potential in applying in optoelectronic devices, such as CMOS-compatible lasers, emission light source of on-chip optical interconnects, thermoelectric devices, QD solar cells, near infrared detectors and so on [1][2][3][4]. The morphology and structure of single-layer QDs was highly required for the future application; however, the part of physical character of multi-layer QDs was better than single-layer for using in optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Morphology and structure evolution of multilayered Ge/Si quantum dots grown by magnetron sputtering

Shu

Huang

Zhang

et al. 2023

Micro & Nano Letters

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We prepared multilayered Si-based Ge quantum dots (Ge/Si QDs) by using magnetron sputtering technique and reported the corresponding morphology evolution. The increased temperature can improve the Si-isolated-layer crystallinity and Ge atom mobility to increase the density, size and spatial distribution uniformity of top-layer QDs. The morphology and vertical correlation between layers of QDs at different temperatures exhibited different phenomena or laws, and had been explained in this work, which made it possible to control the quality of multilayer QDs more effectively in the high-rate growth, and laid a foundation for the industrial production of active layers of optoelectronic devices.

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“…Authors in [27] demonstrated, adopting the potential morphing method and the effective mass approximation, a considerable enhancement of the nonlinear dielectric function and the refractive index (RIs) by increasing the shell thickness with and without impurity. Moreover, luminescent Ge/Si core/shell structure has been studied in [28], authors have grown the super atom-like Ge (core) in a Si shell. They investigated the luminescence properties and observed electroluminescence in the near infrared at room temperature (RT) concluding about radiative recombination mechanism involving field-effect-induced injection via substrate.…”

Section: Introductionmentioning

confidence: 99%

External electric field effect and impact of encapsulating matrix on optical and electronic properties within CdSe/ZnSe core/shell QDs

Jbeli¹,

Yahyaoui²,

Zeiri³

et al. 2021

Phys. Scr.

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In this study, we have carried out a theoretical investigation of CdSe/ZnSe core/shell spherical quantum dot (CSQD) embedded in different dielectric matrix. The effect of surrounding matrix and the external electric field on the linear and third-order nonlinear real and imaginary parts of the dielectric function have been simulated numerically using the effective mass approximation and taking into account the compact density matrix approach. The electronic band structure and corresponding wave functions were calculated by solving the Schrödinger equation in the framework evoked previously. The study revealed a significant blue shift of the transition energies under electric field offering the possibility of adjusting them. In addition, by varying the dielectric matrices enveloping our main structure, it was also found that the choice of the pattern of the matrix is fundamental for the manipulation of the resonance peak energies of the dielectric function. RECEIVED

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Electroluminescence of superatom-like Ge-core/Si-shell quantum dots by alternate field-effect-induced carrier injection

Cited by 14 publications

References 21 publications

Characterization of Light Emission Properties of Impurity Doped Ge/Si Core–Shell Quantum Dots

Characterization of Light Emission Properties of Impurity Doped Ge/Si Core–Shell Quantum Dots

Morphology and structure evolution of multilayered Ge/Si quantum dots grown by magnetron sputtering

External electric field effect and impact of encapsulating matrix on optical and electronic properties within CdSe/ZnSe core/shell QDs

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