Infrared vibrations of interstitial oxygen in silicon-rich SiGe alloys

Humlíček, Josef; Štoudek, Richard; Dubroka, Adam

doi:10.1016/j.physb.2005.12.056

Cited by 7 publications

(7 citation statements)

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“…They were single crystal except for the one with x = 0.066 which was polycrystalline. The Ge contents in the alloys had been determined by mass-density or ellipsometry measurements [7,8]. Photoluminescence has been measured from the samples, immersed in liquid helium, Figure 1.…”

Section: Experimental Techniquesmentioning

confidence: 99%

“…Consequently, the intensity (area) of the each component is proportional to the probability of the structure causing it. Their relative intensities then indicate their origins [6][7][8]. If there are no Ge atoms in any of the 24 second-or third-neighbour sites to the O atom, then the component O i -I is seen near 1136 cm −1 in the limit of small x.…”

Section: Structures Of Sige:omentioning

confidence: 99%

“…The O i -III line, centred near ∼1118 cm −1 , is ascribed to the structure with one Ge atom in one of the six equivalent sites at a second-neighbour position from the O atom, giving a C 1h configuration like Si-O-Si-Ge, with no Ge atoms in any of the 18 thirdneighbour positions, and hence a relative probability of 6x(1 − x) 23 . Two Ge atoms in the second-neighbour sites are suggested to produce absorption to significantly lower energy [8] and so can be ignored here. However, multiple occupation of the third-neighbour sites has not been considered.…”

Section: Configuration Probabilitymentioning

confidence: 99%

“…Alloy broadening is assumed to be proportional to x. Fits to the spectra as in figure 4 reveal that the lineshapes are asymmetric at low T , with the longer tail on the low energy side [8,19]. The lineshape of equation ( 4) has been used, with different widths on each side, as listed in table 2.…”

Section: Fitting At Low Temperaturementioning

confidence: 99%

“…Despite a massive amount of work on the ν 3 absorption band, its shape has only been discussed quantitatively at temperatures T < 80 K [3,4]. In dilute Si 1−x Ge x alloys, with small x, the ν 3 line still occurs near 1130 cm −1 at low T , but contains discrete, alloy-induced structure [5][6][7][8]. The properties of this structure are hidden by alloy and thermal broadening.…”

Section: Introductionmentioning

confidence: 99%

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The spectral bandshape of the ν₃(1136 cm^{− 1}) vibration of oxygen in silicon and dilute silicon–germanium alloys

Davies¹

2010

J. Phys.: Condens. Matter

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At room temperature, the ν(3) (1136 cm(-1)) absorption band of oxygen in silicon and Si(1 - x)Ge(x) alloys consists of dozens of components, masking the properties of the individual transitions. Here, experimental data are presented for the evolution of the ν(3) band in the temperature range 0 < T < 300 K and the composition range 0 ≤ x ≤ 0.066. The vibrational potential for Si:O is developed to provide accurate fits to the absorption data. The potential predicts properties consistent with published studies, including hydrostatic stress experiments. Extending the model to Si(1 - x)Ge(x) allows the properties of the alloy-induced O(i)-I, O(i)-II and O(i)-III components to be investigated accurately to higher values of x than hitherto. The properties of O(i)-I are understood as perturbations by Ge atoms of Si:O, and O(i)-III is rationalized in terms of off-axis movement of the O atom resulting from the nearby Ge atom. Challenges to theory are: the behaviour of O(i)-II, understanding the strain fields generated by Ge atoms in Si, and the reduced coupling of the ν(2) and ν(3) modes with increasing amplitude in the ν(2) mode.

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Section: Experimental Techniquesmentioning

confidence: 99%

Section: Structures Of Sige:omentioning

confidence: 99%