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High-accuracy determination of the dependence of the photoluminescence emission energy on alloy composition in AlxGa1-xAs films
Published
Author(s)
Larry Robins, J T. Armstrong, Ryna B. Marinenko, Albert J. Paul, John Pellegrino, Kristine A. Bertness
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} xless 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]
Robins, L.
, Armstrong, J.
, Marinenko, R.
, Paul, A.
, Pellegrino, J.
and Bertness, K.
(2003),
High-accuracy determination of the dependence of the photoluminescence emission energy on alloy composition in Al<sub>x</sub>Ga<sub>1-x</sub>As films, Journal of Applied Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=30775
(Accessed October 15, 2024)