Cuprous oxide (Cu2O) has been successfully deposited by reactive ion beam sputter deposition at 450 °C with various oxygen flow rates. At high oxygen flow rates, single phase polycrystalline Cu2O thin film was attained while low oxygen flow rates results in the formation of Cu2O nanorods. X-ray diffraction, Raman, and x-ray photoelectron spectroscopy analyses indicate that both samples are composed of Cu2O phase only without the presence of CuO while samples deposited with low oxygen flow rates exhibit improved crystalline quality. Photocurrent measurement result indicates that Cu2O samples prepared under low oxygen flow rate are of n-type. Photoluminescence study suggests that this n-type conductivity is due to the presence of intrinsic oxygen vacancy defects.

In this study, we have successfully deposited n-type Cu2O triangular nanopyramids on Si by employing ion beam sputter deposition with an Ar : O2 ratio of 9 : 1 at a substrate temperature of 450°C. Scanning electron microscopy measurements showed attractively triangular nanopyramids of ∼500 nm edge and height lengths. Both X-ray diffraction and Raman spectroscopy characterizations showed the structures were single-phase polycrystalline Cu2O, and the room-temperature photoluminescence investigation showed interestingly green and blue exciton luminescence emissions. All Mott—Schottky, linear sweep voltammetry, and photocurrent measurements indicated that the conductivity of the Cu2O pyramids is of n-type.

Cu2O has been deposited on quartz substrates by reactive ion beam sputter deposition. Experimental results show that by controlling argon/oxygen flow rates, both n-type and p-type Cu2O samples can be achieved. The bandgap of n-type and p-type Cu2O were found to be 2.3 and 2.5 eV, respectively. The variable temperature photoluminescence study shows that the n-type conductivity is due to the presence of oxygen vacancy defects. Both samples show stable photocurrent response that photocurrent change of both samples after 1,000 seconds of operation is less than 5%. Carrier densities were found to be 1.90 × 1018 and 2.24 × 1016 cm−3 for n-type and p-type Cu2O, respectively. Fermi energies have been calculated, and simplified band structures are constructed. Our results show that Cu2O is a plausible candidate for both photoanodic and photocathodic electrode materials in photoelectrochemical application.

CuO nano/micro rods were deposited on Si substrates by ion beam sputter deposition at substrate temperatures 300 C, 350 C, 400 C and 450 C. The effects of changing substrate temperature on the structural properties and surface morphology of the deposited CuO nano/micro roads were studied. Field Emission Scanning Electron Microscopy micrographs showed that at substrate temperature of 300 C and 350 C, tiny nanoparticles were observed on the surface of CuO thin films and at substrate temperature of 400 C and 450 C, CuO nano/micro rods of lengths (100 nm to 1 µm) observed in a periodic arrangement. X-Ray Diffraction (XRD) analysis showed that all the diffraction peaks of the samples were single-crystalline CuO corresponded to (1 ̅11) orientation. From the crystallographic analysis using XRD data, crystallite sizes of the samples increased (18 to 32 nm) with the increase of substrate temperature. The Micro-Raman spectroscopy investigation shows that all the Raman peaks observed were phonon modes of CuO and as the substrate temperature increased, the intensities of the Rama peaks increased. Hence, by changing substrate temperatures, it is possible to deposit high quality CuO nano/micro thin films with tunable structures, morphologies and sizes for different optoelectronic applications through ion beam sputter deposition.