Investigation on doping behavior of copper in ZnO thin film

An experiment to determine the electronic and chemical states of Cu in a ZnO crystal was performed using Hall measurement, X-ray photoelectron spectroscopy (XPS) and low-temperature photoluminescence (PL). Cu atoms showed different behaviors in the ZnO matrix as a function of oxygen gas pressure. Metallic copper (Cu0)-related Cu 2p3/2 peak was observed in highly n-type ZnO:Cu film deposited in 10 mTorr. In the Cu-doped p-type ZnO film prepared in 50 mTorr, CuZn1+-related peak and small CuZn2+-related satellite peak exhibited and the optical acceptor binding energies of Cu3d9 and Cu3d10 were 173 and 213 meV, respectively.