Generalized far-infrared magneto-optic ellipsometry for semiconductor layer structures: Determination of free-carrier effective-mass, mobility, and concentration parameters in n-type GaAs

Mathias Schubert, Tino Hofmann, Craig M. Herzinger

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

We report for the first time on the application of generalized ellipsometry at far-infrared wavelengths (wave numbers from 150 cm-1 to 600 cm-1) for measurement of the anisotropic dielectric response of doped polar semiconductors in layered structures within an external magnetic field. Upon determination of normalized Mueller matrix elements and subsequent derivation of the normalized complex Jones reflection matrix r of an n-type doped GaAs substrate covered by a highly resistive GaAs layer, the spectral dependence of the room-temperature magneto-optic dielectric function tensor of n-type GaAs with free-electron concentration of 1.6 × 1018 cm-3 at the magnetic field strength of 2.3 T is obtained on a wavelength-by-wavelength basis. These data are in excellent agreement with values predicted by the Drude model. From the magneto-optic generalized ellipsometry measurements of the layered structure, the free-carrier concentration, their optical mobility, the effective-mass parameters, and the sign of the charge carriers can be determined independently, which will be demonstrated. We propose magneto-optic generalized ellipsometry as a novel approach for exploration of free-carrier parameters in complex organic or inorganic semiconducting material heterostructures, regardless of the anisotropic properties of the individual constituents.

Original languageEnglish (US)
Pages (from-to)347-356
Number of pages10
JournalJournal of the Optical Society of America A: Optics and Image Science, and Vision
Volume20
Issue number2
DOIs
StatePublished - Feb 2003

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Computer Vision and Pattern Recognition

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