Heterojunction photovoltaic devices consisting of hybrid p-type organic Cu-phthalocyanine and inorganic n-type Al2O3 nanoparticle-coated aligned ZnO nanorods were fabricated. With microwave treatment, an interaction occurred between the Al2O3 and ZnO, as evidenced from TEM image. This interaction shifts the absorption peak of the aligned nanorods from the UV region to visible light and subsequently causes more charge generation. For 5 mol% Al2O3 nanoparticle-coated aligned ZnO nanorods treated with microwaves of 600 W for 300 sec, the maximum incident photon to electron conversion and energy conversion efficiencies under simulated sunlight of AM1.5G (10 mW/cm2) are 0.036 mA and 1.32%, respectively.