Quantum confinement of E1 and E2 transitions in Ge quantum dots embedded in an Al2O3 or an AlN matrix

Teng, Chunlin; Muth, John F.; Kolbas, R. M.; Hassan, Khaled; Sharma, Ajay; Kvit, A.; Narayan, J.

doi:10.1063/1.125650

Cited by 27 publications

(20 citation statements)

References 17 publications

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“…[6][7][8][9] Germanium QDs embedded in amorphous wide-band-gap matrices like SiO 2 or Al 2 O 3 have numerous interesting properties such as very strong quantum confinement, electroluminescence and photoluminescence, nonlinear refraction index, possibility to retain electric charge for long time, etc. [10][11][12][13][14][15][16] Therefore they have great possibilities for application in nanotechnology, especially for QD-based memories, sensors and solar cells. Recent investigations showed that Al 2 O 3 matrix has many advantages compared to usually used fused silica, since alumina has a higher dielectric constant, excellent thermal and mechanical properties and it is more suitable as a building material for gates in memory devices.…”

Section: Introductionmentioning

confidence: 99%

Self-assembling of Ge quantum dots in an alumina matrix

et al. 2010

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In this work we report on a self-assembled growth of a Ge quantum dot lattice in a single 600-nm-thick Ge+ Al 2 O 3 layer during magnetron sputtering deposition of a Ge+ Al 2 O 3 mixture at an elevated substrate temperature. The self-assembly results in the formation of a well-ordered three-dimensional body-centered tetragonal quantum dot lattice within the whole deposited volume. The quantum dots formed are very small in size ͑less than 4.0 nm͒, have a narrow size distribution and a large packing density. The parameters of the quantum dot lattice can be tuned by changing the deposition parameters. The self-ordering of the quantum dots is explained by diffusion-mediated nucleation and surface-morphology effects and simulated by a kinetic Monte Carlo model.

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Section: Introductionmentioning

confidence: 99%

Self-assembling of Ge quantum dots in an alumina matrix

et al. 2010

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“…Blue shifts and splittings of the E 1 and E 2 transitions were measured in GaAs/AlAs superlattices 3,4 . More recently, a quantum confinement induced shift of E 1 and E 2 was measured in Ge nanoparticles embedded in a glassy matrix 5,6 . A main purpose of this work is to calculate the behavior of E 1 and E 2 transitions upon confinement in GaAs/AlAs superlattices and in free-standing GaAs layers, which are simulated by GaAs/vacuum superlattices.…”

Section: Introductionmentioning

confidence: 99%

Electronic states and optical properties of GaAs/AlAs and GaAs/vacuum superlattices by the linear combination of bulk bands method

Botti

Andreani²

2001

Phys. Rev. B

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The linear combination of bulk bands method recently introduced by Wang, Franceschetti and Zunger [Phys. Rev. Lett. 78, 2819 (1997)] is applied to a calculation of energy bands and optical constants of (GaAs)n/(AlAs)n and (GaAs)n/(vacuum)n (001) superlattices with n ranging from 4 to 20. Empirical pseudopotentials are used for the calculation of the bulk energy bands. Quantumconfined induced shifts of critical point energies are calculated and are found to be larger for the GaAs/vacuum system. The E1 peak in the absorption spectra has a blue shift and splits into two peaks for decreasing superlattice period; the E2 transition instead is found to be split for large-period GaAs/AlAs superlattices. The band contribution to linear birefringence of GaAs/AlAs superlattices is calculated and compared with recent experimental results of Sirenko et al. [Phys. Rev. B 60, 8253 (1999)]. The frequency-dependent part reproduces the observed increase with decreasing superlattice period, while the calculated zero-frequency birefringence does not account for the experimental results and points to the importance of local-field effects.

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“…9 The height sizes of our QDs are permissible to expect the quantum confinement effect. 8 Therefore the observed blue shift is determined by the interplay between above two effects.…”

Section: ωmentioning

confidence: 97%

Tip-Enhanced Rayleigh Scattering and Photoluminescence from Semiconductor Nanoparticles

Ogawa

Katayama²,

Minami³

2011

j nanosci nanotechnol

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Tip-enhanced Rayleigh scattering images of Ge quantum dots grown on a Si substrate have been observed at room temperature. Changing the wavelength of the incidence light from 405 to 590 nm, the contrast of the images is reversed. It is found that the scattering intensity depends on the dielectric constants of the materials under the probe. By changing the wavelength of the incident light, we have obtained information about the dielectric constant dispersion of single Ge quantum dots. The spectral peak position of single Ge quantum dots is found to shift to higher energy, compared to that of bulk Ge. Tip-enhanced photoluminescence from an In0.25Ga0.75N film at room temperature has also been reported. The strong local enhancement of the photoluminescence of the localized excitons has been observed in the vicinity of a gold nano-particle attached to the end of the probe. A coupling to plasmons in the gold nano-particle yields strong enhancement of the photoluminescence.

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Quantum confinement of E1 and E2 transitions in Ge quantum dots embedded in an Al2O3 or an AlN matrix

Cited by 27 publications

References 17 publications

Self-assembling of Ge quantum dots in an alumina matrix

Self-assembling of Ge quantum dots in an alumina matrix

Electronic states and optical properties of GaAs/AlAs and GaAs/vacuum superlattices by the linear combination of bulk bands method

Tip-Enhanced Rayleigh Scattering and Photoluminescence from Semiconductor Nanoparticles

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