Surface modification of thermally evaporated CdTe thin films for sensing application of organic compounds

Abstract

The study involves the growth of bulk cadmium telluride (CdTe) by using vertical directional solidification (VDS) technique. The as grown CdTe compound has been used as a source material to deposit thin films onto glass substrates at room temperature by thermal evaporation technique under high vacuum conditions of 10^-5 mbar. The thickness of film has been measured around 310 nm. Characterization of bulk CdTe compound and its thin films have been done by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and photoluminescence (PL) techniques. CdTe thin films have been then used for exposure to vapors of organic compounds such as acetone, formaldehyde, methanol, ethanol, benzene, toluene and chloroform in order to ascertain the use of these films for various sensors. The optical and micro structural properties of CdTe thin films have been studied using PL and AFM techniques so as to evaluate the sensing capabilities of CdTe thin film towards specific compounds which have been used for exposure.