Electric fields separation by phase selection in modulation spectroscopy of photoreflectance

Y. C. Wang, W. Y. Chou, W. C. Hwang, J. S. Hwang

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7 Citations (Scopus)


The built-in electric fields in a MBE grown δ-doped GaAs homojunction have been investigated by the techniques of photoreflectance and phase suppression. Two Franz-Keldysh oscillation features originating from two different fields in the structure superimpose with each other in the photoreflectance spectrum. By properly selecting the reference phase of the lock-in amplifier, one of the features can be suppressed, thus enabling us to determine the electric fields from two different regions. We have demonstrated that only two PR spectra, in-phase and out-phase components, are needed to find the phase angle which suppresses one of the features. The electric field in the top layer is 3.5 ± 0.2 × 105 V cm-1, which is in good agreement with theoretical calculation. The electric field in the buffer layer is 1.2 ± 0.1 × 104 V cm-1, which suggests the existence of interface states at the buffer/substrate interface.

Original languageEnglish
Pages (from-to)717-721
Number of pages5
JournalSolid State Communications
Issue number12
Publication statusPublished - 1997 Dec

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry


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