MAGNETIC AND OPTICAL PROPERTIES OF CHEMICAL BATH DEPOSITED Al/Pb-SULPHIDE/OXIDE THIN FILMS

Abstract

Oxide and sulphide of Al/Pb were prepared using the Chemical Bath Deposition (CBD) technique at room temperature (303K) for deposition period of 2.5 hours, 3.5 hours, 4.5 hours and 5.5 hours. Nano crystalline thin films of thickness 100-780 nm were fabricated in the study. The absorbance decreases with increase in wavelength and has relatively low values in the infrared region (IR) of the electromagnetic spectrum. Highest values of absorbance were seen at a period of 3.5 hours for PbO, 3.5 hours and 5.5 hours for PbS, 2.5 hours for Al2S3 and 5.5 hours for Al2S3 at wavelength range between 275 nm to 310 nm, hence the films possess potential application within this region. The transmittance increases as the wavelength increases, values greater than 85% were obtained for transmittance spectra of PbO, while the PbS gives transmittance in the range 10-35%. The very high transmittance in the visible region suggests the suitability of the films for solar energy collector and aesthetic window glaze materials. On the other hand, the low reflectance values of the thin films reveal their importance as material for anti-reflection coating. These results show that, thin films of Al/Pb oxide and sulphide can also be used as optical sensors. The direct band gap energy for the films deposited ranges between 1.8 - 3.4 eV. Except for the thickness, the study revealed that varying the time of deposition has no significant effect on the magnetic properties of the thin films. Key words: CBD method, Al/Pb oxide and sulphide, period of deposition, optical properties, magnetic properties.