Temperature dependence of optical properties of GaAs

Huade Yao, Paul G. Snyder, John A Woollam

Research output: Contribution to journalArticle

77 Citations (Scopus)

Abstract

Pseudodielectric functions 〈ε〉= 〈ε1〉+i〈ε2〉 of GaAs were measured by spectroscopic ellipsometry (SE), in the range of 1.6-4.45 eV, at temperatures from room temperature (RT) to ∼610 °C. A very clean, smooth surface was obtained by first growing an epitaxial layer of GaAs on a GaAs substrate and immediately capping it with a protective layer of arsenic. The cap prevented surface oxidation during transport to the measurement chamber, where it was evaporated under ultrahigh vacuum at ∼350 °C. Room-temperature SE results from this surface are in good agreement with those in the literature obtained by wet-chemical etching. A quantitative analysis of the 〈ε〉 spectrum was made using the harmonic-oscillator approximation (HOA). It is shown by the HOA that the E1 and E11 energy-band critical points shift downward ∼300 meV as temperature increases from RT to ∼610 °C. An algorithm was developed, using the measured optical constants at a number of fixed temperatures, to compute the dielectric function spectrum at an arbitrary temperature in the range of 22-610 °C. Therefore, the ellipsometer can be utilized as an optical thermometer to determine the sample surface temperature.

Original languageEnglish (US)
Pages (from-to)3261-3267
Number of pages7
JournalJournal of Applied Physics
Volume70
Issue number6
DOIs
StatePublished - Dec 1 1991

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optical properties
temperature dependence
harmonic oscillators
ellipsometry
room temperature
ellipsometers
temperature
thermometers
approximation
caps
arsenic
quantitative analysis
ultrahigh vacuum
surface temperature
energy bands
critical point
chambers
etching
oxidation
shift

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Temperature dependence of optical properties of GaAs. / Yao, Huade; Snyder, Paul G.; Woollam, John A.

In: Journal of Applied Physics, Vol. 70, No. 6, 01.12.1991, p. 3261-3267.

Research output: Contribution to journalArticle

Yao, Huade ; Snyder, Paul G. ; Woollam, John A. / Temperature dependence of optical properties of GaAs. In: Journal of Applied Physics. 1991 ; Vol. 70, No. 6. pp. 3261-3267.
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