High-Accuracy Determination of the Dependence of the PhotoluminescenceEmission Energy on Alloy Composition in AlxGa1-xAs Films

Published

April 1, 2003

Author(s)

Lawrence H. Robins, J T. Armstrong, Ryna B. Marinenko, Albert J. Paul, J G. Pellegrino, Kristine A. Bertness

Abstract

In an effort to improve the accuracy of photoluminescence (PL)spectroscopy as a composition (Al mole fraction) measurement method forthe Al_xGa_1-xAs alloy system, the PL peak emission energy,E_PL,peak, was measured at room temperature for a set of MBE-grownAl_xGa_1-xAs films with Al mole fraction 0 {less than or equalto} x {less than} 0.37, and correlated with x as measured independently byin-situ reflective high-energy electron diffraction (RHEED) and also byex-situ wavelength-dispersive x-ray spectroscopy in an electronmicroprobe analyzer (WDS/EMPA). The measurement uncertainty ofE_PL,peak was minimized through calibration of the photon energy scaleand spectrometer response, fitting the corrected data using a carefullychosen empirical lineshape function (asymmetric bell-curve), andmeasuring and compensating for the effect of ambient temperature drift.To enable accurate compensation of the temperature drift, a separate setof measurements was done to determine the temperature coefficientsdE_PL,peak ÷ dT near room temperature. With these procedures,the 2 ς measurement uncertainty of E_PL,peak was typically of theorder 5 × 10^-4 eV. From correlation of the PL andWDS/EMPA results, the slope of the function E_PL,peak(x) near roomtemperature was determined to be dE_PL,peak ÷ dx=(1.4017 {plusor minus} 0.0090 eV)-((2.71 {plus or minus} 0.97) × 10^-4eV ÷ K)(T - 298.3 K). Correlation of the PL and RHEED resultsyielded an identical slope within measurement uncertainty. Previouslypublished measurements of dE_PL,peak ÷ dx are compared withthe present study. Possible reasons for the large variation in thepublished values of dE_PL,peak ÷ dx are discussed. Theresults of T.F. Kuech et al. (Appl. Phys. Lett. 51, 505 (1987)), whichare based on nuclear resonant reaction analysis of the Al mole fraction,were found to be in good agreement with the present study after additionof a correction term to account for the difference in sample temperature(T=2 K for Kuech et al., T=298 K for the present study).

Citation

Journal of Applied Physics

Volume

93

Issue

No. 7

Pub Type

Journals

Keywords

alloy composition, aluminum gallium arsenide, chemical composition, compound semiconductors, gallium arsenide, luminescence spectroscopy, photoluminescence, RHEED, WDS

Citation

Robins, L. , Armstrong, J. , Marinenko, R. , Paul, A. , Pellegrino, J. and Bertness, K. (2003), High-Accuracy Determination of the Dependence of the PhotoluminescenceEmission Energy on Alloy Composition in Al_xGa_1-xAs Films, Journal of Applied Physics (Accessed April 19, 2024)