In this study We employ the x-ray energy dispersive spectrometry technique to characterize AlxGa((1-x))As layers with sinusoidal grading in the Al content, using a field emission gun transmission electron microscope. The Al/Ga composition profiles were determined based on the Cliff-Lorimer (CL) equations, assuming the thin-foil criterion. The sensitivity factors in the CL equations (k(Al-As), k(Ga-As), and k(Al-Ga)) required for calculating,the composition profiles were determined from precalibrated AlxGa(1-x)As layers. An alternate procedure, wherein the Ga composition is calculated using only k(Ga-As) determined from GaAs, was also investigated. The results from this approach were in good agreement with those obtained based on sensitivity factors determined from the precalibration layers. The measured As profile indicates that the composition of AlxGa(1-x)As can be measured to an accuracy of similar to+/-0.02 in x. (C) 2004 American Vacuum Society.