Characteristics of Quantum Dots and Single-Phase p-CuInSe2 Nanowire Arrays Electrodeposited as Schottky Diodes with a Silver Contact

Abstract

CuInSe2 nanowire (NW) arrays were prepared in a heated electrolyte (45°C) through anodized aluminum oxide template–assisted pulse electrodeposition. After the CuInSe2 NWs were as-grown, grazing incidence X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) revealed the recrystallization status of the CuInSe2 NWs annealed at temperatures ranging from 250°C to 550°C. The results indicated that the NWs underwent a phase transformation from the (204/220) plane to the (112) plane. Additionally, the material particle size and quantum dots were measured using HRTEM and ultraviolet/visible spectroscopy. The particle size of the as-grown CuInSe2 NWs ranged from 3.8 to 8 nm. The as-grown CuInSe2 NWs exhibited a blue-shift in the material absorption band at 1100 and 1200 nm compared with those annealed at 550°C. The results of scanning electron microscopy had a diameter and length of 80 nm and 2.2 μm, respectively. Mott–Schottky and ohmic contact plots revealed that the CuInSe2 NWs were p-type semiconductors. Moreover, the different leakage current mechanisms of the nonideal Schottky diode were studied. Finally, near-ideal Schottky barrier diodes were obtained at an annealing temperature of 550°C, and their work function was estimated to be in the range of 5.04–5.13 eV.