Raman and modulated-reflectivity spectra of a strained pseudomorphic ZnTe epilayer on InAs under pressure

Robert J. Thomas, Mark S. Boley, H. R. Chandrasekhar, Meera Chandrasekhar, C. Parks, A. K. Ramdas, J. Han, Masakazu Kobayashi, R. L. Gunshor

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Abstract

The piezomodulated-, electromodulated-, and photomodulated-reflectivity spectra of a pseudomorphic ZnTe epilayer, grown on an InAs epilayer by molecular-beam epitaxy, exhibit heavy- and light-hole excitonic signatures split by the lattice mismatch induced biaxial compressive strain. This splitting in the pseudomorphic epilayer is studied as a function of applied hydrostatic pressure using photomodulated reflectance spectroscopy at 80 K. With increasing hydrostatic compression, the compressive strain is progressively compensated by the pressure-induced tensile strain. At ∼55 kbars the epilayer becomes strain-free, and is under a biaxial tension at higher pressures. The separation between the heavy- and light-hole signatures is superlinear in pressure, suggestive of a strain or volume deformation-dependent shear deformation-potential constant. We also compare the pressure dependence of the Raman LO phonon of the ZnTe epilayer on InAs with that of a bulk ZnTe sample at 13 K. The pressure-dependent strain is found to be linear. Accurate values of the first-order strain derivatives of the LO phonons and mode Grüneisen constants are obtained.

Original languageEnglish
Pages (from-to)2181-2184
Number of pages4
JournalPhysical Review B
Volume49
Issue number3
DOIs
Publication statusPublished - 1994
Externally publishedYes

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ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Thomas, R. J., Boley, M. S., Chandrasekhar, H. R., Chandrasekhar, M., Parks, C., Ramdas, A. K., Han, J., Kobayashi, M., & Gunshor, R. L. (1994). Raman and modulated-reflectivity spectra of a strained pseudomorphic ZnTe epilayer on InAs under pressure. Physical Review B, 49(3), 2181-2184. https://doi.org/10.1103/PhysRevB.49.2181