We have studied the local atomic structure around Zn and Cd, in CdSe, ZnSe, and ordered and disordered Zn0.5Cd0.5Se thin films, grown by molecular beam epitaxy (MBE) and atomic layer epitaxy (ALE) using X-ray absorption spectroscopy (XAS). Zn K-shell X-ray absorption fine structure (XAFS) shows that the Zn-Se pair nearest neighbor distance is the same in both ordered and disordered ternary samples. This result shows that the ordered (or disordered growth) does not have a significant effect in the nearest neighbor Zn environment. However, results from K-shell Cd XAFS show that the U-Se pair nearest neighbor distance in the Zn0.5Cd0.5Se ordered film exhibits a contraction compared to the same pair distance in the disordered Zn0.5Cd0.5Se sample and the binary CdSe compound. This suggests that the shortest Zn-Se nearest neighbor distance regulates the Zn-Se nearest neighbor distance in the ternary compounds, when these are grown in an ordered, layer by layer, fashion. (c) 2005 Elsevier B.V. All rights reserved.