We investigated the effect on the electronic properties of aluminum (Al)-zinc oxide (ZnO) films by modulating the radio frequency sputtering power. Our experimental results show that increasing the sputtering power increases the Al doping concentration, decreases the resistivity, and also shifts the Zn 2p and O 1s to higher binding energy states. Our local-density approximation (LDA) and LDA+U calculations show that the shift in higher binding energy and resistivity decrease are due to an enhancement of the O 2p-Zn 3d coupling and the modification of the Zn 4s-O 2p interaction in ZnO induced by Al doping. ; PUBLISHED ; This work was supported by the Air Force Office for Scientific Research (Award No. FA9550-08-1-0134) and the University of Idaho New Faculty Start-up Fund. H.C.W. and I.V.S. acknowledge the financial support from Science Foundation of Ireland (SFI) under Contract No. 06/IN.1/I91.