Work function alteration of the porous indium tin oxide nanorods film by electron beam irradiation technique

Abstract

Material properties of transparent conductive oxide (TCO), such as crystallinity and work function, have been recognized as important factors affecting a performance of optoelectronic devices. In this work, a nuclear technique, electron beam irradiation, is proposed as a post deposition technique to alter the material characteristics of an indium tin oxide (ITO) nanorods film. The ITO film is fabricated by ion-assisted electron beam evaporation with glancing-angle deposition (GLAD) technique and subsequently irradiated by an electron beam with energy up to 20 MeV at the absorbed doses of 100 kGy and 300 kGy. The effect of irradiation, in terms of morphology and crystallinity, is studied by scanning electron microscopy (SEM), grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM). Whereas, the photoemission spectroscopy (PES) is carried out to study the surface composition and the work function of the ITO films. The SEM result indicates that the diameter of the ITO nanorods increases due to the electron beam irradiation. The electron beam induced crystallization of the ITO nanorod is observed and confirmed by both XRD and TEM measurements. Furthermore, the PES results reveal a change in the surface chemical composition and the work function of the ITO film after the electron beam irradiation. The results of this study implies that the electron beam irradiation serves as a promising post deposition treatment to improve the properties of ITO film, especially in terms of work function alteration.