Optical and photoconductivity studies of Cu2O nanowires synthesized by solvothermal method

The solvothermal method has been employed to synthesize cuprous oxide (Cu2O) nanowires using a precursor of cupric acetate monohydrate (CuAc2) and ethylene glycol (EG) as the solvent. By optimizing the reaction temperature and reaction time, we have prepared Cu2O nanowires with a diameter of approximately 7 nm and a length of several nanometers. The UV-visible absorption spectrum of the nanowires shows obvious blueshift compared to the bulk Cu2O, which arises from the quantum confinement effect of the excitonic transition expected for Cu2O nanowires. Here we also report the role of different excitation energies on the photoluminescence (PL) properties of the Cu2O nanowires by steady-state and time-resolved PL spectroscopy. The decay times vary from nanoseconds to picoseconds. Decay kinetics indicates that the average lifetime 〈τ〉 of the nanowires increases with increasing excitation energy. The current-voltage (I-V) curves of the nanowires give the photocurrent density 16 times larger than the dark current density.