Optical properties of Mn-doped InAs and InMnAs epitaxial films

P. T. Chiu, A. J. Blattner, S. J. May, B. W. Wessels*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The optical properties of In1-xMnxAs ferromagnetic semiconductors have been measured over the spectral range of 0.05-3.5eV to determine their electronic structure. For single-phase InMnAs alloy thin films (x<0.01-0.12), a band gap of 0.334eV, 23meV lower than InAs, is observed at 295 K. The decrease is attributed to the formation of a shallow manganese impurity band. Reflectance peaks arising from higher lying L-point transitions between the valence band and conduction band are observed in InMnAs thin films. The energy of these transitions decreases with increasing manganese concentration. This demonstrates that the manganese impurity band broadens at the L-point. A broad featureless absorption band was observed between 0.05 and 0.30eV.This extrinsic absorption band is attributed to light hole to heavy hole inter-valence band transitions. The measured low-frequency optical conductivity is in good agreement with that determined from electrical resistivity measurements.

Original languageEnglish (US)
Pages (from-to)379-384
Number of pages6
JournalPhysica B: Condensed Matter
Volume344
Issue number1-4
DOIs
StatePublished - Feb 15 2004

Funding

This work is supported by the NSF under the Spin Electronics Program #ECS-0224210. Extensive use of the Keck facility at Northwestern University is acknowledged.

Keywords

  • Diluted magnetic semiconductors
  • Indium manganese arsenide
  • Infrared spectroscopy
  • Spintronics
  • Visible reflectance

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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