Fabrication and characterization of Cu-CdSe-Cu nanowire heterojunctions

The Cu-CdSe-Cu nanowire heterojunctions were fabricated by sequential electrochemical deposition of layers of Cu metal and CdSe semiconductor within the nano-pores of anodic alumina membrane templates. X-ray diffraction reveals the cubic phase for Cu and hexagonal phase for CdSe in the electrodeposited Cu-CdSe-Cu nanowire heterojunctions. The composition of the nanowire heterojunction segments is characterized by energy dispersive X-ray spectroscopy. The morphological study of nanowire heterojunctions has been made using scanning electron microscope and high resolution transmission microscopy. The nanowire heterojunctions grown in 100 and 300 nm nano-pore size templates have been found to have optical band gaps of 1.92 and 1.75 eV, respectively. The absorption spectra of 100 nm nanowire heterojunctions show a blue shift of 0.18 eV. The collective nonlinear current-voltage (I-V) characteristics of the 300 and 100 nm nanowire heterojunctions show their rectifying and asymmetric behaviour, respectively.