An investigation of modifications induced by silver ion beam in selenium nanowires

Selenium nanowires with a diameter of 80 nm were deposited on a copper substrate at room temperature by template-assisted electrodeposition. These one-dimensional nanostructures were irradiated by 120 MeV silver ions with fluencies ranging from 1 x 10(11) ions/cm(2) to 1 x 10(12) ions/cm(2). Pristine and irradiated samples have been characterized by scanning electron microscopy, X-ray diffraction, UV-visible spectroscopy, photoluminescence and current-voltage characterization to determine their structural, optical and electrical properties modification. The diffraction patterns reveal no peak shifts upon irradiation with Ag ions but variations in peak intensity was clearly visible, which is a direct reflection of alteration of the crystallographic orientation of the planes. The crystallite size for the pristine and irradiated samples was calculated using Debye Scherrer equation and the variation observed is insignificant. Current voltage analysis shows a significant variation in the conductivity with the ion fluence. A modification in the optical band gap was also depicted after irradiation, formation of intermediate energy states may be probable cause for this alteration. The variation in conductivity may be due to the generation of charge carriers, development of intermediate energy states in the forbidden energy band and irradiation-induced defects.