Effects of annealing on optical and electrical characteristics of p-type semiconductor copper (II) oxide electrodeposits

The 1.35-eV-bandgap energy-CuO film with the optical absorption coefficient of 2.2 × 104 cm− 1 has been prepared on a conductive glass substrate by anodic electrodeposition in an aqueous solution containing copper (II) nitrate and ammonium nitrate at 298 K followed by annealing at 573 K and above in air. The as-deposited CuO film with a monoclinic lattice showed p-type conduction with resistivity of 2.2 × 105 Ω cm and slightly expanded bandgap energy of 1.46 eV with the absorption coefficient of 1.3 × 104 cm− 1. The annealing induced changes in the grain morphology, bandgap energy, absorption coefficient, and resistivity, and the resistivity of 3.3 Ω cm could be obtained by annealing at 773 K.