MOVPE growth conditions (e.g. growth temperature, growth rates, V/III ratio, and TMA/(TMA+TMG) ratio) effect on the All incorporation into AlGaN were systemically investigated. High-resolution X-ray diffraction (HRXRD), Energy dispersive X-ray spectroscopy (EDX) and cathodoluminescence (CL) were used to characterize the structural, compositional and optical properties of AlGaN. The results showed that at the same growth temperature, Al incorporation efficiency is very high even if the ratio of TMA/ (TMA + TMG) is relatively small. Moreover, the Al concentration in solid AlGaN increased with a increase of growth temperature. The NH3 flow rate has little effect on the Al content in AlGaN and the Al incorporation efficiency was reduced with an increase in growth rate. (c) 2006 Elsevier B.V. All rights reserved.