Modification of quantum dots in Ge/Si nanostructures by pulsed laser irradiation

Володин, В. А.; Yakimov, A. I.; Двуреченский, А. В.; Efremov, M. D.; Nikiforov, A. I.; Gatskevich, E. I.; Ивлев, Г. Д.; Mikhalev, G. Yu.

doi:10.1134/s1063782606020175

Cited by 10 publications

(13 citation statements)

References 11 publications

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“…Since the amount of Ge deposited as well as the growth and overgrowth temperatures are the same for all three samples this finding provides evidence that intermixing in self-organized GeSi QDs proceeds by a surface diffusion process [21][22][23] rather than a bulk interdiffusion mediated by nonuniform stress fields [24][25][26]. The average lateral strain xx (= yy ) in Ge nanoclusters can be estimated from the Ge-Ge phonon frequency ω Ge-Ge using the following empirical relation [27] ω Ge-Ge = 300. 3…”

Section: Raman Spectroscopymentioning

confidence: 81%

Effect of the growth rate on the morphology and structural properties of hut-shaped Ge islands in Si(001)

et al. 2006

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The effect of Ge deposition rate on the morphology and structural properties of self-assembled Ge/Si(001) islands was studied. Ge/Si(001) layers were grown by solid-source molecular-beam epitaxy at 500 °C. We adjusted the Ge coverage, 6 monolayers (ML), and varied the Ge growth rate by a factor of 100, R = 0.02-2 ML s(-1), to produce films consisting of hut-shaped Ge islands. The samples were characterized by scanning tunnelling microscopy, Raman spectroscopy, and Rutherford backscattering measurements. The mean lateral size of Ge nanoclusters decreases from 14.1 nm at R = 0.02 ML s(-1) to 9.8 nm at R = 2 ML s(-1). The normalized width of the size distribution shows non-monotonic behaviour as a function of R and has a minimum value of 19% at R = 2 ML s(-1). Ge nanoclusters fabricated at the highest deposition rate demonstrate the best structural quality and the highest Ge content (∼0.9).

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Section: Raman Spectroscopymentioning

confidence: 81%

Effect of the growth rate on the morphology and structural properties of hut-shaped Ge islands in Si(001)

et al. 2006

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“…A contribution from Ge vapor phase deposition to the formation of drops on the sur face cannot be ruled out as well. The formation of sim ilar island structures was observed in Ge/Si and SiGe/SiO 2 films subjected to PLA or ion beam annealing [12][13][14] as well as to rapid thermal annealing (at 900°C for 60 s) [15] with melting of the Ge layers.…”

Section: Investigation Of the Structure And Optical Propertiesmentioning

confidence: 99%

Pulsed modification of germanium films on silicon, sapphire, and quartz substrates: Structure and optical properties

et al. 2015

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The structural and optical properties of thin Ge films deposited onto semiconducting and insulat ing substrates and modified by pulsed laser radiation are studied. The films are deposited by the sputtering of a Ge target with a low energy Xe + ion beam. Crystallization of the films is conducted by their exposure to nanosecond ruby laser radiation pulses (λ = 0.694 μm) with the energy density W = 0.2-1.4 J cm -2 . During pulsed laser treatment, the irradiated area is probed with quasi cw (quasi continuous wave) laser radiation (λ = 0.532 and 1.064 μm), with the reflectance recorded R(t). Experimental data on the lifetime of the Ge melt are compared with the results of calculation, and good agreement between them is demonstrated. Through the use of a number of techniques, the dependences of the composition of the films, their crystal structure, the level of strains, and the reflectance and transmittance on the conditions of deposition and annealing are established.

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“…In Ge/Si, one way to suppress misfit dislocations is to lower the growth temperature [7]. Pulsed ion-beam irradiation during heteroepitaxy of Ge on Si led to modifying the average size and size distribution of Ge islands grown by molecular beam epitaxy (MBE) and post-deposition nanosecond pulsed laser treatment of Ge QD grown on Si reduced the QD surface density, modified their composition and increased their average size, making the QD size more uniform after the treatment [8].…”

Section: Introductionmentioning

confidence: 99%

STM study of pulsed laser assisted growth of Ge quantum dot on Si(1 0 0)-(2 × 1)

Elsayed-Ali

2014

Eur. Phys. J. Appl. Phys.

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Ge quantum dot formation on Si(1 0 0)-(2 × 1) by nanosecond pulsed laser deposition under laser excitation was investigated. Scanning tunneling microscopy was used to probe the growth mode and morphology. Excitation was performed during deposition using laser energy density of 25-100 mJ/cm 2. Faceted islands were achieved at a substrate temperature of ∼250 • C only when using laser excitation. The island morphology changes with increased laser excitation energy density although the faceting of the individual islands remains the same. The size of the major length of islands increases with the excitation laser energy density. A purely electronic mechanism of enhanced surface diffusion of the Ge adatoms is proposed. 2 Experiment Germanium quantum dots were grown in an ultrahigh vacuum (UHV) chamber (∼ 7×10 −11 Torr) by PLD equipped with STM. The Ge target was rotated at 6 rpm to minimize particle formation during deposition. The laser beam profile on target and target rotation speed were set such

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Modification of quantum dots in Ge/Si nanostructures by pulsed laser irradiation

Cited by 10 publications

References 11 publications

Effect of the growth rate on the morphology and structural properties of hut-shaped Ge islands in Si(001)

Effect of the growth rate on the morphology and structural properties of hut-shaped Ge islands in Si(001)

Pulsed modification of germanium films on silicon, sapphire, and quartz substrates: Structure and optical properties

STM study of pulsed laser assisted growth of Ge quantum dot on Si(1 0 0)-(2 × 1)

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