Abstract: This work presents the successful deposition of Lead Silver Sulphide (PbAgS) by simple chemical bath method under varying pH conditions. Varying pH was achieved using different volume concentration of ammonium hydroxide (NH4OH) solution. The final bath solution for the deposition of the films contained aqueous solutions of Pb(NO3)2, AgNO3, thiourea, TEA and EDTA. Pb(NO3)2, AgNO3 and thiourea served as precursors for Pb2+, Ag+, and S2- respectively while EDTA and TEA were used as complexing agents. NH4OH served as pH adjuster. The deposited film properties were characterized for optical and electrical properties using a Janway UV – VIS spectrophotometer and 4 Point Probe (Keithley Four Point Probe: Model 67005). From the spectral analysis of absorbance, other optical properties such as transmittance, reflectance, refractive index, and extinction coefficient and band gap energy were obtained. The films show high absorbance in the UV region and high transmittance in the VIS – NIR regions, while reflectance is generally low. The films showed direct band gap energy range of 1.89 eV – 2.30 eV. The result showed that band gap decreased as pH increases. Film thickness increased from 493.83 nm to 945.52 nm as pH increases. Electrical properties of the films showed that the deposited PbAgS thin films are semiconducting films with electrical conductivity within the range of 1.337 × 10-3 (s/cm) and 9.334 × 10-3 (s/cm). Electrical conductivity of the films were found to increase as pH increases from 10.30 to 11.20.
Abstract: This work presents the successful deposition of Lead Silver Sulphide (PbAgS) by simple chemical bath method under varying pH conditions. Varying pH was achieved using different volume concentration of ammonium hydroxide (NH4OH) solution. The final bath solution for the deposition of the films contained aqueous solutions of Pb(NO3)2, AgNO3, thiourea, TEA and EDTA. Pb(NO3)2, AgNO3 and thiourea served as precursors for Pb2+, Ag+, and S2- respectively while EDTA and TEA were used as complexing agents. NH4OH served as pH adjuster. The deposited film properties were characterized for optical and electrical properties using a Janway UV – VIS spectrophotometer and 4 Point Probe (Keithley Four Point Probe: Model 67005). From the spectral analysis of absorbance, other optical properties such as transmittance, reflectance, refractive index, and extinction coefficient and band gap energy were obtained. The films show high absorbance in the UV region and high transmittance in the VIS – NIR regions, while reflectance is generally low. The films showed direct band gap energy range of 1.89 eV – 2.30 eV. The result showed that band gap decreased as pH increases. Film thickness increased from 493.83 nm to 945.52 nm as pH increases. Electrical properties of the films showed that the deposited PbAgS thin films are semiconducting films with electrical conductivity within the range of 1.337 × 10-3 (s/cm) and 9.334 × 10-3 (s/cm). Electrical conductivity of the films were found to increase as pH increases from 10.30 to 11.20.