DUAL SOLUTION SYNTHESIS AND CHARACTERIZATION OF PbO:SnO2, CuO:SnO2, CdO:SnO2 AND ZnO:SnO2 ALLOYED THIN FILMS FOR POSSIBLE DEVICE APPLICATIONS

SOURCE:

Faculty: Physical Sciences
Department: Physics And Industrial Physics

CONTRIBUTORS:

Onwuemeka, J.I;
Ekwo, P.I;
Ekpunobi, A.J;

ABSTRACT:

PbO:SnO2, CuO:SnO2, CdO:SnO2, and ZnO:SnO2 alloyed thin films were successfully synthesized on glass substrates under the deposition condition of 60oC of NaOH solution, using two solution based methods: successive ionic layer adsorption and reaction (SILAR) and solution growth technique. The deposited alloyed samples were annealed between 100oC to 250oC using Master Chef Annealing Machine.The crystallographic studies were done using X-ray diffractometer (XRD) and scanning electron microscope (SEM).The XRD pattern of PbO:SnO2 alloyed thin films of samples A11 and A12 with one diffraction peak at 2θ = 22.300 with corresponding Miller indices (111) and the grain size of the alloys is 92.29nm.The XRD pattern of CdO:SnO2 alloyed thin films of samples A14 and A16 with diffraction peak at 2θ = 15.400 and with corresponding Miller indices (111). The grain size of the samples is calculated is 91.41nm. The XRD of CuO:SnO2 alloyed thin films of A21 and A22 show no crystalline peak(s) thereby confirming the amorphous nature of the films.The XRD pattern of ZnO:SnO2 alloyed thin films of samples A24and A25with two diffraction peaks at 2θ=19.5220 and 22.8110 with corresponding Miller indices (111) and (200).The XRD pattern shows crystallinity of the alloyed ZnO:SnO2. The grain sizes were found to be 40.522nm and 92.41nm.Rutherford backscattering Spectroscopy (RBS) analysis confirmed the percentage of the elements of tin, lead, copper, zinc, cadmium and oxygen in the alloyed thin films. The optical characterization was carried out using UV-1800 double beam spectrophotometer. The alloyed thin films of samples A11 and A12 of PbO:SnO2 show optical transmittance of 32%-70% in the ultraviolet region, 70%-76% in the visible, and 75%-71% in the near-infrared regions of electromagnetic spectrum for sample A11annealed at 250oC. Sample A12 annealed at 200oC has an optical transmittance of 21% -81% in the ultraviolet region, 81% -75% in the visible and 75%-80% in the near infrared regions of electromagnetic spectrum. The two samples, have average direct wideband gap of 3.65±0.05eV. The alloyed thin films of samples A21 and A22 of CuO:SnO2show optical transmittance of 45%-64% in the ultraviolet region, 65%-74% in the visible, and 75%-77% in the near-infrared regions of electromagnetic spectrum for sample A21 annealed at 150oC. Sample A22 annealed at 250oC has an optical transmittance of 42% -62% in the ultraviolet region, 62% -69% in the visible and 68%-74% in the near infrared regions of electromagnetic spectrum. The two samples, have average direct wide band gap of 3.30±0.05eV. The alloyed thin films of samples A14 and A16 of CdO:SnO2 show optical transmittance of 16%-60% in the ultraviolet region, 61%-59% in the visible, and 59%-58% in the near-infrared regions of electromagnetic spectrum for sample A14 annealed at 100oC. Sample A16 annealed at 150oC has an optical transmittance of 27% -70% in the ultraviolet region, 70% -84% in the visible and 81%-85% in the near infrared regions of electromagnetic spectrum. The two samples, have average direct wide band gap of 3.78±0.05eV. The alloyed thin films of samples A24 and A25 ZnO:SnO2 show optical transmittance of 42%-60% in the ultraviolet region, 60%-61% in the visible, and 62%-58% in the near-infrared regions of electromagnetic spectrum for sample A24 annealed at 200oC. Sample A25 annealed at 150oC has an optical transmittance of 49% -63% in the ultraviolet region, 63% -65% in the visible and 65%-68% in the near infrared regions of electromagnetic spectrum. The two samples, have averagedirect wide band gap of 3.37±0.05eV. Other optical properties that were investigated are; absorbance, reflectance absorption coefficient, extinction coefficient, refractive index, opticalconductivity, and dielectric constants. From the spectral qualities, these compound alloyed thin films may be found useful in cold and heat mirror applications, galvanization metal surfaces to avoid corrosion, vulcanization in tyre production, active layer in various types of solar cells, liquid crystal displays, flat panel displays for opto-electronic applications and gas censor applications.