Electrical and optical activation studies of AlxGa1-xN (x = 0.11 and 0.21) implanted with silicon were made as a function of ion dose and anneal temperature. Silicon ions were implanted at 200 keV with doses ranging from 1 x 10(14) to 1 s 10(15) cm(-2) at room temperature. The implanted samples were subsequently annealed from 1100 to 1300 degrees C for 20 min in a nitrogen environment. A maximum electrical activation efficiency of 91% was obtained for the Al0.11Ga0.89N implanted with the highest dose of 1 x 10(15) cm(-2) even after annealing at 1150 degrees C. 100% activation efficiencies were successfully obtained for the Al0.21Ga0.79N samples after annealing at 1300 degrees C for both doses of 5 x 10(14) and 1 x 10(15) cm(-2). The mobility of the Si-implanted AlxGa1-xN increases with annealing temperature, and the highest mobilities are 109 and 98 cm(2)/V.s for Al0.11Ga0.89N and Al0.21Ga0.79N, respectively. The cathodoluminescence (CL) spectra for all the samples exhibited a sharp neutral-donor-bound exciton peak, and the CL intensity increases with annealing temperature, indicating successive improved implantation damage recovery as the annealing temperature is increased. These results provide the optimum annealing conditions for activation of implanted Si ions in AlxGa1-xN (C) 2011 Elsevier B.V. All rights reserved.