Carrier-induced strain effect in Si and GaAs nanocrystals

Zhao, Xiaonan; Ge, Y. R.; Schroeder, John; Persans, P. D.

doi:10.1063/1.112999

Cited by 40 publications

(23 citation statements)

References 14 publications

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“…This may indicate the presence of nanocrystalline material within the hardness indents instead of the original single crystalline wafer material. 31,34 A further sign of ductile behaviour was observed in scratch experiments on GaAs at liquid nitrogen temperatures (Fig. 5), when plastic deformation by dislocation gliding was suppressed.…”

Section: Gallium Arsenide and Indium Antimonidementioning

confidence: 74%

Raman microspectroscopy of nanocrystalline and amorphous phases in hardness indentations

Kailer¹,

Nickel²,

Gogotsi³

1999

J. Raman Spectrosc.

160

131

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During hardness indentation, materials are subjected to highly localized stresses. These stresses not only cause crack formation and plastic deformation by dislocation gliding, but a complete change of the crystal structure and formation of amorphous phases or high-pressure polymorphs can occur in the zone of maximum contact stresses. Such contact-induced phase transformations were observed in hard and brittle materials including semiconductors (Si, Ge, GaAs and InSb) and common ceramic materials such as SiC and SiO 2 (a-quartz and silica glass). A prime tool for their investigation is the Raman microspectroscopy of hardness indentations. In Si and Ge, there is an initial transformation to metallic high-pressure phases upon hardness indentation and a subsequent formation of crystalline, nanocrystalline, or amorphous phases depending on the conditions of the hardness test, in particular the unloading rate. A phase transformation occurs also in InSb, whereas the results for GaAs do not give sufficient evidence for phase transformations. Indentationinduced amorphization has been observed in SiC and quartz. Even diamond has been shown to undergo amorphization and phase transformation under nonhydrostatic stress conditions imposed by indentation tests.Plate 1. Light micrograph of (a) a Vickers impression in diamond, (b) typical Raman spectrum from the central part of the impression and Raman intensity images showing (c) distribution of diamond and (d) graphite. Colour change from dark blue to yellow indicates the increase of the Raman band intensity from zero to the maximum. (Excitation wavelength: 632.8nm)

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Section: Gallium Arsenide and Indium Antimonidementioning

confidence: 74%

Raman microspectroscopy of nanocrystalline and amorphous phases in hardness indentations

Kailer¹,

Nickel²,

Gogotsi³

1999

J. Raman Spectrosc.

160

131

View full text Add to dashboard Cite

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“…[13]). As for the generation of the intermediate peak (peak II), there might be different possible origins: (i) a downshift of the wavenumber for the Si phonon could be due to the existence of nanocrystals [14] because of the phonon confinement effect, although it is questionable to generate nanocrystalline silicon in the single-crystalline substrate without external treatment like machining, loading etc; (ii) another possibility is that of disorder-induced change of the line shape. This disorder would be originated from the stress induced by the large lattice mismatch and localized at the interface between the SiC epilayer and the Si substrate, which was in good agreement with the experimental results that it appeared only at Points 5 and 6 (cf.…”

Section: Resultsmentioning

confidence: 99%

Phase transformation of Si upon epitaxial CVD growths of β‐SiC layer on Si substrates

Zhu

Wan

et al. 2006

Physica Status Solidi (a)

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PACS 78.30. Am, 81.15.Gh Micro-Raman spectroscopy was applied to investigate the stress relaxation in the CVD growth of SiC on silicon substrates. We observed a double-peak feature of the LO + 2TO silicon phonon in as-grown SiC/Si samples, and tentatively ascribed it to phase transformation of silicon during the epitaxial growth. Stress analysis around the featured regions suggested that it might be related with incomplete relief of local stress, such as appearance of micropipes in suitable circumstances.

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“…4 are visible in only three experiments. Possible origins of these bands, taking into account the shift due to the compressive stress, could be assigned to either the formation of Si nanocrystals, 22,23 Si-IV (hexagonal diamond structure) phases, [10][11][12][13]24 or regions with extensive cracking. 4.…”

Section: Discussionmentioning

confidence: 99%

In situ compression tests on micron-sized silicon pillars by Raman microscopy—Stress measurements and deformation analysis

et al. 2008

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Mechanical properties of silicon are of high interest to the microelectromechanical systems community as it is the most frequently used structural material. Compression tests on 8 μm diameter silicon pillars were performed under a micro-Raman setup. The uniaxial stress in the micropillars was derived from a load cell mounted on a microindenter and from the Raman peak shift. Stress measurements from the load cell and from the micro-Raman spectrum are in excellent agreement. The average compressive failure strength measured in the middle of the micropillars is 5.1 GPa. Transmission electron microscopy investigation of compressed micropillars showed cracks at the pillar surface or in the core. A correlation between crack formation and dislocation activity was observed. The authors strongly believe that the combination of nanoindentation and micro-Raman spectroscopy allowed detection of cracks prior to failure of the micropillar, which also allowed an estimation of the in-plane stress in the vicinity of the crack tip.

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Carrier-induced strain effect in Si and GaAs nanocrystals

Cited by 40 publications

References 14 publications

Raman microspectroscopy of nanocrystalline and amorphous phases in hardness indentations

Raman microspectroscopy of nanocrystalline and amorphous phases in hardness indentations

Phase transformation of Si upon epitaxial CVD growths of β‐SiC layer on Si substrates

In situ compression tests on micron-sized silicon pillars by Raman microscopy—Stress measurements and deformation analysis

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