Impedance Spectroscopy and Dielectric Properties of Silver Incorporated Indium Sulfide Thin Films

Abstract

In this study, silver incorporated indium sulfide (In2S3) thin films have been deposited on soda lime glass via spray pyrolysis technique. Structural and electrical properties have been tailored by adding controlled amount of silver acetate into the precursor solution. A phase shift form cubic -In2S3 to AgInS2 has been evidenced from X-ray diffraction spectra (XRD). Molecularity of the samples, meaning (Ag+In)/S ratio, has directly affected the electrical conductivity as well as the dielectric properties. Direct and alternating current conductivities increased with increasing the (Ag+In)/S ratio upto 10% silver incorporation. When the silver amount further increased conductivity decreased due to the pronounced secondary phase formation. The complex impedance analysis was used to determine the effect of silver on the conduction mechanism. It has been observed that frequency exponent of all samples were greater than unity indicating the nanocrystalline nature of the films. The variation of dielectric properties and ac conductivity with frequency revealed that the relaxation process in silver incorporated In2S3 thin films was due to the Maxwell–Wagner type of interfacial polarization in general.