Large asymmetric Stark shift in GaxIn1−xAs/InP/InAsyP1−y composite quantum wells

Aneeshkumar, B.; Silov, A. Yu.; Leys, Maarten; Wolter, J.H.

doi:10.1063/1.1616664

Cited by 9 publications

(8 citation statements)

References 17 publications

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“…10,11 In InGaAs/GaAs near-surface QW, large blueshifts in the transition energy were observed experimentally and theoretically by several groups. The large blueshifts induced by the quantum confined Stark effect in asymmetric and composite quantum wells were reported.…”

Section: Resultsmentioning

confidence: 93%

“…1 In case of the QW-surface coupling, which was considered as a quantum coupling, the field effect was neglected. 10,11 In dielectric QWs like NSQW the electronic structure is not only determined by the quantum confinement effect, but is also influenced by the dielectric effect, i.e., the Coulomb interaction between an electron and a hole is also influenced by their image charges formed at the semiconductor-vacuum interface. This calculation showed strong redshifts (up to 40 meV) and a decrease in intensity of the GaAs/ AlGaAs QW peak for surface barrier thickness below 150 Å .…”

Section: Introductionmentioning

confidence: 99%

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Blueshift in sulfur treated GaAsP/AlGaAs near surface quantum well

Pal¹,

Singh²,

Porwal³

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Comparative study on passivation of GaAs 0.86 P 0.14 / Al 0.6 Ga 0.4 As near-surface quantum well Photoreflectance and photoluminescence spectroscopy of the lattice-matched InGaAs/InAlAs single quantum well J. Appl. Phys. 92, 920 (2002); 10.1063/1.1487906Photoluminescence and photo-modulated reflectance spectra of ion-implanted GaAs/AlGaAs coupled quantum wells Large blueshift was observed in a near-surface GaAs 0.86 P 0.14 /Al 0.7 Ga 0.3 As quantum well upon treatment with Na 2 SÁxH 2 O solution. Very slow etching with simultaneous surface passivation of the quantum well was obtained using this chemical treatment. Photoreflectance (PR) spectra exhibit maximum blueshift of 28 meV after treating the quantum well surface with Na 2 SÁxH 2 O solution for 30 min (top layer thickness reduced to 10 Å ). The blueshift is attributed to an increase in the confinement and/or an image charge effect due to the penetration of the wave function into vacuum. The blueshift is accompanied by a significant reduction in the broadening parameter of the observed e 1 -lh 1 transition in PR spectra indicating effective passivation along with an increase in the confinement.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Blueshift in sulfur treated GaAsP/AlGaAs near surface quantum well

Pal¹,

Singh²,

Porwal³

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…Our method provides larger changes than the small perturbations in energy levels that can be achieved with applied heating [10,11], stress [12], and magnetic [13] or electric fields [14][15][16][17][18]. This concept is shown here for interband transitions but it may have its largest impact on intersubband transitions, where the energy state tuning will be limited only by thermal broadening at low energies and band offsets at high energies.…”

Section: Introductionmentioning

confidence: 93%

Coupling of quantum states with mechanical heterostructures

Makowski

Anderson

Chan

et al. 2009

TRANSDUCERS 2009 - 2009 International Solid-State Sensors, Actuators and Microsystems Conference

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Mechanical positioning is used to control the wavelength of light emission from semiconductor heterostructures. In our work, a Si x N/InP cantilever containing an InGaAs surface well collapses over another InGaAs quantum well. The spacing between the wells varies along the collapsed cantilever, changing the coupling between heterostructures and thus the electron states. In an essence, we are altering the bandgap by the mechanical bending of the cantilever. This is very much similar to the control of photon states by coupling optical cavities with tunable mirrors. Here we report a wavelength shift of up to 22 nm in photoluminescence measurements of two coupled 200 Å surface wells. Associated theory shows that mechanical quantum coupling enables interband or intersubband devices with unprecedented spectral tuning ranges for gain or absorption.

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“…Surprisingly, a few researchers observed a redshift of the ground state transition energy for the NSQW, which was explained by considering either the effect of the built-in electric field, i.e. the quantum-confined Stark effect [2,17] or the interaction of QW-confined states with the surface states [18]. At the moment, there is neither the clarity nor the consensus among researchers on the effect of top barrier layer thickness on the ground state transition energy of the NSQW.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Effect of light-hole tunnelling on the excitonic properties of GaAsP/AlGaAs near-surface quantum wells

Pal

Singh

Porwal

et al. 2013

Semicond. Sci. Technol.

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Light-hole tunnelling to the surface states is studied using photoluminescence (PL) spectroscopy and transient reflectivity measurements in the tensile-strained GaAsP/AlGaAs near-surface quantum well (NSQW) samples by reducing the top barrier layer thickness from 275 to 5 nm. The ground state transition (e 1 -lh 1 ) remains excitonic even at room temperature (RT) for a buried quantum well sample with 275 nm thick top barrier. When the top barrier thickness is reduced to 50 nm the same transition is found to be excitonic only at low temperatures but changes to free-carrier recombination at higher temperatures. When the top barrier layer thickness is further reduced to 5 nm, the ground state transition is no longer excitonic in nature, where it shows free-carrier behaviour even at 10 K. We therefore find a clear relationship between the character of the ground state transition and the top barrier layer thickness. Light-hole excitons cannot be formed in NSQW samples when the top barrier layer thickness is kept reasonably low. This is attributed to the quantum mechanical tunnelling of free light holes to the surface states, which is found to be faster than the exciton formation process. A tunnelling time of ∼500 fs for light holes is measured by the transient reflectivity measurements for the NSQW sample with a 5 nm top barrier. On the other hand, heavy-hole-related transitions in NSQW samples are found to be of excitonic nature even at RT because of the relatively large tunnelling time. It supports the dominance of excited state feature over the ground state transition in PL measurements at temperatures higher than 150 K.

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Large asymmetric Stark shift in GaxIn1−xAs/InP/InAsyP1−y composite quantum wells

Cited by 9 publications

References 17 publications

Blueshift in sulfur treated GaAsP/AlGaAs near surface quantum well

Blueshift in sulfur treated GaAsP/AlGaAs near surface quantum well

Coupling of quantum states with mechanical heterostructures

Effect of light-hole tunnelling on the excitonic properties of GaAsP/AlGaAs near-surface quantum wells

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