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Publication Citation: High-accuracy Determination of the Dependence of the Photoluminescence Emission Energy on Alloy Composition in AlxGa1-xAs Films

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Author(s): Lawrence H. Robins; J T. Armstrong; Ryna B. Marinenko; Albert J. Paul; John Pellegrino; Kristine A. Bertness;
Title: High-accuracy Determination of the Dependence of the Photoluminescence Emission Energy on Alloy Composition in AlxGa1-xAs Films
Published: April 01, 2003
Abstract: In an effort to improve the accuracy of photoluminescence (PL) measurements of the Al mole fraction (x) of AlxGa1-xAs alloys, the PL peak emission energy, EPL,peak, was measured at room temperature for molecular-beam epitaxy-grown AlxGa1-xAs films with 0 {less than or equal to} x{less than}0.37, and correlated with independent measurements of x by in situ reflective igh-energy electron diffraction (RHEED) and also by ex situ wavelength-dispersive x-ray spectroscopy in an electron microprobe analyzer (WDS/EMPA). The measurement uncertainty of EPL,peak was minimized through the following procedures: Accurate calibration of the photon energy (or wavelength) scale, correction of the measured spectra for the spectrometer response function, fitting the data with a well-chosen line shape function, and compensation for the effect of ambient temperature drift. With these procedures, the 2ς measurement uncertainty of EPL,peak was of the order 5 x 10-4 eV for most samples. From correlation of the PL and WDS/EMPA composition data, the slope dEPL,peak/dx near room temperature was determined to be dEPL,peak/dx=(1.4017 ±0.0090 eV) -[(2.71±0.97)x 10-4 eV/K](T-298.3 K0. Correlation with the RHEED data gave the same result within measurement uncertainty. Previously published measurements of dE^dPL,peak/dx were reviewed and compared with the present study. The results of T.F. Kuech et al. [Appl. Phys. Lett. 51, 505 (1987)], based on nuclear resonant reaction analysis of the Al mole fraction, were found to be in good agreement with the present study after the addition of a correction term to account for the sample temperature difference (T=2 K for Kuech et al., T=298 K for present study). [DOI: 10.1063/1.1556554]
Citation: Journal of Applied Physics
Volume: 93
Issue: 7
Pages: pp. 3747 - 3759
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