Dielectric response of thick low dislocation-density Ge epilayers grown on (001) Si

Junge, Kelly; Lange, R.; Dolan, Jennifer L.; Zollner, Stefan; Dashiell, M. W.; Orner, B. A.; Kolodzey, J.

doi:10.1063/1.117826

Cited by 15 publications

(8 citation statements)

References 6 publications

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“…This might be attributed to the presence of threading dislocations and small compressive strain in the nearly relaxed films. 27,30 The phase angles for E 1 and E 1 þ D 1 obtained for the film are in good agreement with the bulk values. We notice that the magnitude of phase angle for E 1 is slightly greater than that for E 1 þ D 1 for both our film and bulk, consistent with the finding for bulk InSb 11 at room temperature.…”

Section: Resultssupporting

confidence: 78%

Mid-infrared to ultraviolet optical properties of InSb grown on GaAs by molecular beam epitaxy

D'Costa

Tan

Jia

et al. 2015

Journal of Applied Physics

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Section: Resultssupporting

confidence: 78%

Mid-infrared to ultraviolet optical properties of InSb grown on GaAs by molecular beam epitaxy

D'Costa

Tan

Jia

et al. 2015

Journal of Applied Physics

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“…The error in the shift determined from this procedure is probably quite large, but it is apparent that a downshift of the E 1 and E 1 + Δ 1 transitions takes place. Similarly we observe a red shift of the E 2 critical point of about 50 meV from a derivative analysis of spectroscopic ellipsometry data . These data suggest that the band gap of the alloys is also reduced relative to Ge, although it is not possible from this information to determine whether the expected indirect-direct transition has taken place.…”

Section: Resultsmentioning

confidence: 96%

Synthesis of Silicon-Based Infrared Semiconductors in the Ge−Sn System Using Molecular Chemistry Methods

et al. 2001

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Growth reactions based on a newly developed deuterium-stabilized Sn hydride [(Ph)SnD(3)] with Ge(2)H(6) produce a new family of Ge-Sn semiconductors with tunable band gaps and potential applications in high-speed, high-efficiency infrared optoelectronics. Metastable diamond-cubic films of Ge(1-x)Sn(x) alloys are created by chemical vapor deposition at 350 degrees C on Si(100). These exhibit unprecedented thermal stability and superior crystallinity despite the 17% lattice mismatch between the constituent materials. The composition, crystal structure, electronic structure, and optical properties of these materials are characterized by Rutherford backscattering, high-resolution electron microscopy, and X-ray diffraction, as well as Raman, IR, and spectroscopic ellipsometry. Electron diffraction reveals monocrystalline and perfectly epitaxial layers with lattice constants intermediate between those of Ge and alpha-Sn. X-ray diffraction in the theta-2theta mode shows well-defined peaks corresponding to random alloys, and in-plane rocking scans of the (004) reflection confirm a tightly aligned spread of the crystal mosaics. RBS ion-channeling including angular scans confirm that Sn occupies substitutional lattice sites and also provide evidence of local ordering of the elements with increasing Sn concentration. The Raman spectra show bands corresponding to Ge-Ge and Sn-Ge vibrations with frequencies consistent with random tetrahedral alloys. Resonance Raman and ellipsometry spectra indicate a band-gap reduction relative to Ge. The IR transmission spectra suggest that the band gap decreases monotonically with increasing Sn fraction. The synthesis, characterization, and gas-phase electron diffraction structure of (Ph)SnD(3) are also reported.

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“…Broadening parameter for E 1 is also found to be sensitive to the dislocation density in group-IV alloys. 24 Pseudomorphic SiGeC alloys which have lower dislocation density than relaxed alloys show narrow broadening parameters. Phase angle is related to the geometrical nature of a critical point and is also assumed to capture the many body effects.…”

Section: Introductionmentioning

confidence: 99%

Compositional dependence of optical critical point parameters in pseudomorphic GeSn alloys

D'Costa

Wang

Zhou

et al. 2014

Journal of Applied Physics

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Spectroscopic ellipsometry was used to investigate the optical response of pseudomorphic Ge 1Àx Sn x (0 x 0.17) alloys grown directly on Ge (100) by molecular beam epitaxy. A detailed compositional study of amplitudes, broadenings, energies, and phase angles associated with critical points E 1 , E 1 þ D 1 , E 0 0 , and E 2 of GeSn alloys was carried out using a derivative analysis. The results can be understood in terms of the electronic bandstructure of Ge or relaxed GeSn alloys with the following differences. First, broadening parameters in pseudomorphic alloys are found to have lower values compared to relaxed alloys indicating lower dislocation density in our pseudomorphic alloys relative to relaxed alloys. Second, the amplitudes of E 1 and E 1 þ D 1 are enhanced and reduced, respectively, with respect to relaxed GeSn alloys, and the trends are captured using the k.p method as a biaxial stress induced effect. Third, phase angles are lower than Ge for all the critical points suggesting reduction of excitonic effects in GeSn with respect to Ge.

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Dielectric response of thick low dislocation-density Ge epilayers grown on (001) Si

Cited by 15 publications

References 6 publications

Mid-infrared to ultraviolet optical properties of InSb grown on GaAs by molecular beam epitaxy

Mid-infrared to ultraviolet optical properties of InSb grown on GaAs by molecular beam epitaxy

Synthesis of Silicon-Based Infrared Semiconductors in the Ge−Sn System Using Molecular Chemistry Methods

Compositional dependence of optical critical point parameters in pseudomorphic GeSn alloys

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