Formation of self-assembled ZnTe quantum dots on ZnSe buffer layer grown on GaAs substrate by molecular beam epitaxy

Kuo, M. C.; Yang, C. S.; Tseng, P. Y.; Lee, J.; Shen, Ji‐Lin; Chou, Wu–Ching; Shih, Yu-Ting; Ku, Chin-Yu; Lee, Meng-Chieh; Chen, Wei–Kuo

doi:10.1016/s0022-0248(02)01421-5

Cited by 11 publications

(4 citation statements)

References 14 publications

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“…ZnTe/ZnSe multiple quantum dot (QD), quantum well (QW), and superlattice (SL) structures with type-II staggered band alignment have been previously grown with the aim of achieving tunable optical properties via quantum confinement effects. 4,[9][10][11] The carrier confinement in type-II systems, such as ZnTe/ZnSe is independent of the bandgaps of the underlying materials, but rather depends on the band offsets. Thus, incorporation of Mg in this material system will allow us to control band offsets, hence the confinement energies, as well as to engineer the ZnTe/ZnSe bandgaps at the nanoscale.…”

Section: Introductionmentioning

confidence: 99%

Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures

Manna

Noyan

Zhang

et al. 2012

Journal of Applied Physics

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We report the structural properties and spatial ordering of multilayer ZnMgTe quantum dots (QDs) embedded in ZnSe, where sub-monolayer quantities of Mg were introduced periodically during growth in order to reduce the valence band offset of ZnTe QDs. The periodicity, period dispersion, individual layer thickness, and the composition of the multilayer structures were determined by comparing the experimental high resolution x-ray diffraction (HRXRD) spectra to simulated ones for the allowed (004) and quasi-forbidden (002) reflections in combination with transmission electron microscopy (TEM) results. Secondary ion mass spectroscopy (SIMS) profiles confirmed the incorporation of Mg inside the QD layers, and the HRXRD analysis revealed that there is approximately 32% Mg in the ZnMgTe QDs. The presence of Mg contributes to higher scattering intensity of the HRXRD, leading to the observation of higher order superlattice peaks in both the (004) and (002) reflections. The distribution of scattered intensity in the reciprocal space map (RSM) shows that the diffuse scattered intensity is elongated along the q x axis, indicating a vertical correlation of the dots, which is found to be less defined for the sample with larger periodicity. The diffuse scattered intensity is also found to be weakly correlated along the q z direction indicating a weak lateral correlation of the dots. V

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Section: Introductionmentioning

confidence: 99%

Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures

Manna

Noyan

Zhang

et al. 2012

Journal of Applied Physics

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“…Previously, ZnTe/ZnSe multiple quantum dot (QD), quantum well (QW), and superlattice (SL) structures with type-II band alignment have been grown in hopes of achieving tunable optical properties via quantum confinement effects. [4][5][6][7] Apart from their optical tunability, ZnTe/ZnSe heterostructures are of interest for advancing the bipolar doping of "difficult to dope" ZnSe-based alloys, 8,9 since the latter can be readily doped n-type, while ZnTe can be doped p-type. Introduction of sub-monolayer quantities of ZnTe within the ZnSe matrix led to the simultaneous formation of Te isoelectronic center and ZnTe rich QDs embedded in the ZnSe.…”

Section: Introductionmentioning

confidence: 99%

Radiative transitions in stacked type-II ZnMgTe quantum dots embedded in ZnSe

Manna¹,

Zhang²,

Dhomkar³

et al. 2012

Journal of Applied Physics

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Pronounced Purcell enhancement of spontaneous emission in CdTe/ZnTe quantum dots embedded in micropillar cavities Appl. Phys. Lett. 101, 132105 (2012) Fabrication and photoluminescence of SiC quantum dots stemming from 3C, 6H, and 4H polytypes of bulk SiC Appl. Phys. Lett. 101, 131906 (2012) Anomalous temperature dependence of photoluminescence in self-assembled InGaN quantum dots Appl. Phys. Lett. 101, 131101 (2012) Optical properties of multi-stacked InGaAs/GaNAs quantum dot solar cell fabricated on GaAs (311)B substrate J. Appl. Phys. 112, 064314 (2012) Tunable electroluminescence from polymer-passivated 3C-SiC quantum dot thin films Sub-monolayer quantities of Mg are introduced in multilayer stacked ZnMgTe quantum dots (QDs) embedded in ZnSe barriers in order to reduce the hole confinement energy by controlling the bandgaps and band-offsets of ZnTe/ZnSe system having type-II band alignment. The photoluminescence (PL) emission from such ZnMgTe/ZnSe QD structure is found to be a broad band centered at 2.35 eV. The higher energy side of the PL band shows a larger blue-shift with increasing excitation intensity and a faster life-time decay due to a greater contribution of the emission from the smaller size dots and the isoelectronic bound excitons. It is found that the characteristic decay time of the PL evolves along the band with a value of 129 ns at 2.18 eV to 19 ns at 2.53 eV. The temperature dependent PL emission is controlled by two thermally activated processes: ionization of electrons away from QD state to the barrier (E A1 $ 3 meV) by breaking the type-II excitons and thermal escape of the holes from the ground state to the barrier (E A2 $ 114-116 meV). We propose a modified band diagram and energy levels for this ZnMgTe/ ZnSe multilayer QD system by determining the composition of Mg inside the QDs and solving the 1-D Schrodinger's equation and show that Mg incorporation lowers the hole activation energy via modification of the valence band offset without changing the barrier significantly. V C 2012 American Institute of Physics. [http://dx.

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“…This makes a detailed characterization of these materials the subject of much investigation (1 -3). ZnSe x Te 1-x is an example of a II-VI semiconductor pseudo binary alloy that can be made over the entire range of composition (3)(4)(5). The recent suggestion that high speed logic circuits can be made out of devices using spin diffusion instead of electron diffusion (so-called spintronics) is adding extra impetus for research on these materials (6).…”

Section: Introductionmentioning

confidence: 99%

Pulse Electrodeposited ZnSeTe Films

Murali¹,

Florence²,

John

2012

ECS Trans.

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ZnSexTe1-x films were deposited by pulse electrodeposition technique for the first time. The films exhibited cubic structure. With lattice parameter increasing from 0.579 to 0.605 nm as the Te content increased. Band gap values in the range of 2.35 eV - 2.69 eV are observed as the ZnSe concentration increased. Refractive index was found to vary from 2.83 - 2.53 with increase of 'x' value. Raman spectra exhibit the ZnSe like LO phonons. Photoluminescence spectra of ZnSe1-xTex films with different tellurium content confirms that the Te isovalent impurities exactly replace the Se atoms whose electronic configurations are the same.

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Formation of self-assembled ZnTe quantum dots on ZnSe buffer layer grown on GaAs substrate by molecular beam epitaxy

Cited by 11 publications

References 14 publications

Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures

Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures

Radiative transitions in stacked type-II ZnMgTe quantum dots embedded in ZnSe

Pulse Electrodeposited ZnSeTe Films

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