Physical properties of aluminum doped Zinc Oxide thin films and single wall carbon nanotubes bilayers with potential application in photovoltaics devices

Abstract

A study of transparent thin films of Zinc Oxide doped with Aluminum (AZO) processed by sputtering with potentials application as substrate for single wall carbon nanotubes processing by spray-coating is discussed in this work. AZO Thin films have been deposited by radiofrequency magnetron sputtering technique at room temperature in high vacuum ambient and using an Argon atmosphere. The AZO thin films and the processed bilayers of Zinc Oxide: Aluminum/Single wall carbon nanotubes were characterized by scanning electron microscopy, Raman spectroscopy, x-ray diffraction, ultraviolet-visible spectrophotometry, stylus profilometry and four-terminal method for the electrical resistivity measurement. The feasibility of the Zinc Oxide doped with Aluminum thin films for its use as single wall Carbon Nanotubes substrate processed by a low-cost technique, with potential application in the configuration of photovoltaics devices is presented, analyzed and discussed as function of its electrical, morphological and optical properties through Haacke figure of merit quantification. A two-order reduction in resistivity values, average acceptable transmittance values (∼80%), and crystallinity expected for polycrystalline films were obtained for AZO/Single wall carbon nanotubes bilayers; although the homogeneity of the single wall carbon nanotubes distribution on AZO thin films processed by RF-Sputtering should be improved, the possible application as transparent electrode in a usual configuration of solar cells of AZO/Single wall carbon nanotubes can be performed.