Optical and Electrical Properties of Pure and Y-Doped n-SnSe Films Deposited by Chemical Bath Deposition

Abstract

Pure and Y3+-doped SnSe films were fabricated by chemical bath deposition. The deposited films were characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, ultraviolet–visible spectrophotometry, photoluminescence spectrophotometry, and electrical conduction measurement. Since the films were deposited from the precursor solution with Se/Sn < 1, the Se/Sn molar ratios in the films was also smaller than the stoichiometric ratio. The films had thicknesses of ~409–615 nm and average transmittances of ~73.45–84.10% in the wavelength range of 350–850 nm. The direct and indirect optical band gaps estimated from the optical spectra with two methods of calculating absorption coefficiency. These bandgap values increased as decreasing Y3+-doping content. The films also showed a strong emission centered at ~699 nm and a weak emission centered at ~510 nm. The films showed n-type conduction and electrical resistance of ~5.83–96.40 × 10−3 Ω cm that decreased with increasing Y content. The refractive index, extinction coefficient, optical conductivity, and dielectric constant of the films were calculated with the transmittance and reflectance spectra.