Size dependent properties of one dimensional CdSe micro/nanostructures

Cadmium Selenide (CdSe) micro/nanowires of different diameters were synthesized in polycarbonate membranes on copper substrate by template assisted electro-deposition method at room temperature. The structure, morphology, elemental, optical and electrical properties of CdSe micro/nanowires were investigated using X-ray Diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy and probe station assisted with Keithley source meter. Structural analysis by X-ray diffraction depicted polycrystalline nature with hexagonal phase of micro/nanowires at all diameters. An increase in the value of average crystallite size was seen with increase in diameter. Morphological investigation confirmed the micro/nanowire synthesis and revealed an ordered array of prepared CdSe micro/nanowires of uniform diameters and having high aspect ratios. Optical band gap is found to increase from 1.89eV to 2.24 eV as the diameter is decreased from 1 µm to 50 nm. Using the band gap values, refractive index and optical dielectric constants (static and high frequency) were also evaluated. The electrical conductivity of CdSe micro/nanowires varied from 21.58 × 102 Ω−1 m−1to 1.93 × 102 Ω−1 m−1 when diameter was decreased. These semiconducting micro/nanowires arrays of different diameters may have potential applications in future nanoscale based electronic and optoelectronic devices.