Semiconducting Cu-doped AlOx films fabricated by drop-photochemical deposition

Cu-doped aluminum oxides (AlOx) thin films were deposited by the drop photochemical deposition method using an aqueous solution containing Al(NO3)3, Cu(NO3)2 and Na2S2O3. After deposition, the films were annealed at 400 °C for 60 min. The Cu-doped AlOx films showed p-type photoresponse in a photoelectrochemical measurement. Moreover, while negligible electrical conductivity was detected for non-doped AlOx on an insulating substrate, electrical conduction was clearly observed for the Cu-doped films with resistivity of the order of 108 cm. The junction between non-doped AlOx and Cu-doped AlOx showed rectification and thus was considered to be a p-n junction. Thus, the conductivity and conduction type of aluminum oxide was controlled by Cu doping.