ABSTRACT

CuS:ZnS, CdS:ZnS, AlS:ZnS and SnS:ZnS multilayer thin films were synthesized on glass substrates using two solution based methods: successive ionic layer adsorption and reaction (SILAR) and solution growth technique(SGT). The deposited alloyed samples were annealed between 373K and 523K using Master Chef Annealing Machine. The crystallographic studies were done using X-ray diffractometer (XRD) and scanning electron microscope (SEM). The XRD pattern of CuS:ZnS alloyed thin films of samples P5 and P6show well defined peaks. The XRD pattern of CdS:ZnS alloyed thin films of sample Q5 show well defined peaks. The XRD pattern of AlS:ZnS alloyed thin films of samples R1 and R6 show well defined peaks. The XRD pattern of SnS:ZnS alloyed thin films of sample T6 show well defined peaks which reveals the samples are polycrystalline in nature. Their grain sizes were calculated. Rutherford backscattering spectroscopy (RBS) analysis confirmed the percentage of the elements of copper, cadmium, aluminium, tin, zinc and sulphur in the alloyed thin films. The surface electron microscopy result indicates the microstructure of the deposited alloyed thin films. The optical characterization was carried out using spectrophotometer. The spectral transmittance of samples P0, P1, P2, P3, and P4 show maximum transmissions of 44%, 98%, 78%, 96% and 57% at wavelength of about 900nm throughout the studied region and band gap of 3.98eV, 4.20eV, 4.18eV, 4.21eV and 4.15eV respectively. The spectral transmittance of samples Q0, Q1, Q2, Q3, and Q4 show maximum transmissions of 80%, 90%, 95%, 88% and 97% at wavelength of about 900nm, 900nm, 400nm, 650nm and 470nm within the studied region and band gap of 4.20eV, 4.21eV, 4.15eV and 4.19 respectively. The spectral transmittance of samples R0, R2, R3, R4, and R5 show maximum transmissions of 67%, 82%, 88%, 97% and 70% at wavelength of about 900nm within the studied region and band gap of 4.02eV, 4.20eV, 4.25eV, 4.35eV and 4.15eV respectively. The spectral transmittance of samples T0, T2, T3, T4, and T5 show maximum transmissions of 35%, 40%, 37%, 80% and 82% at wavelength of about 900nm within the studied region and band gap of 3.68eV, 3.8eV, 3.7eV, 3.98eV and 3.9eV respectively. Other optical properties that were investigated are; absorbance, reflectance, absorption coefficient, extinction coefficient, refractive index, optical conductivity and dielectric constants. From the qualities, these sulphide multilayer thin films may be found useful in window coating, vulcanization, etc.