The Phase Evolution and Physical Properties of Binary Copper Oxide Thin Films Prepared by Reactive Magnetron Sputtering

P-type binary copper oxide semiconductor films for various O(2) flow rates and total pressures (P(t)) were prepared using the reactive magnetron sputtering method. Their morphologies and structures were detected by X-ray diffraction, Raman spectrometry, and SEM. A phase diagram with Cu(2)O, Cu(4)O(3), CuO, and their mixture was established. Moreover, based on Kelvin Probe Force Microscopy (KPFM) and conductive AFM (C-AFM), by measuring the contact potential difference (V(CPD)) and the field emission property, the work function and the carrier concentration were obtained, which can be used to distinguish the different types of copper oxide states. The band gaps of the Cu(2)O, Cu(4)O(3), and CuO thin films were observed to be (2.51 ± 0.02) eV, (1.65 ± 0.1) eV, and (1.42 ± 0.01) eV, respectively. The resistivities of Cu(2)O, Cu(4)O(3), and CuO thin films are (3.7 ± 0.3) × 10(3) Ω·cm, (1.1 ± 0.3) × 10(3) Ω·cm, and (1.6 ± 6) × 10(1) Ω·cm, respectively. All the measured results above are consistent.