Optical, structural, and electrical properties of Cu2O thin films

Glancing-angle deposition (GLAD) was used in this work to grow transparent oxide Cu2O thin films by annealing in air at 185 degrees C of copper films deposited firstly by this method onto glass substrates. The annealing temperature of 185 degrees C corresponds to the optimal temperature that corresponds to the formation of Cu2O phase. The copper was sculptured into a zigzag shape, which present case (i) one column with inclined angle theta, case (ii) two columns with inclined angles theta and -theta, and case (iii) three copper inclined columns with inclined angles theta, -theta, and theta where is the deposition angle between the incident flux and the substrate surface normal. The films after annealing have thicknesses of 165, 185, and 265 nm for cases (i), (ii), and (iii), respectively. The air-annealed copper films were characterized for their structural, surface morphological; electrical and optical properties by using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity, and optical (transmittance and reflectance) measurement techniques. Optical studies show a direct allowed transition around 2.5 eV for the three cases. High absorptions coefficients in the range 2 x 10(5)-3.7 x 10(6) cm(-1) were found for photon energies higher than 2.7 eV. The Cu2O films exhibit in cases (i) and (ii) p-type conductivity but in case (iii) the Cu2O films exhibit n-type conductivity. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim