This work deals with the deposited cadmium sulfide (CdS) quantum dots thin films on transparent conductive fluorine-doped tin oxide (FTO) substrates prepared by successive ionic layer adsorption and reaction technique (SILAR). QD deposition based on SILAR is easy, cheap and effective method which improves the surface quality and performance of QD-based devices. The effect of the number of cycles of SILAR on the morphology and size of the quantum dots has been investigated. SILAR technique was adopted for the deposition of CdS on anatase TiO2 and the three main factors contributing to the performance of QDs processed by SILAR, namely the number of cycles used, the concentration of the precursor solution, and the reaction dipping time, are discussed. The structural, morphological and optical properties were studied using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Raman spectra analysis and UV-Vis NIR analysis, respectively. The particle size of CdS was calculated from XRD pattern using Debye Scherrer’s equation and the calculated particle size was 4.5-9.5 nm. Using CdSQDs, quantum dot sensitized solar cells (QDSSC) were fabricated on FTO substrates as being a transparent conductive oxide. Optical absorption property proved that the band gap energy value was about 2.44 eV. The result delivered from J-V curve revealed that the overall energy conversion efficiency increased with increasing the deposition cycles giving the best efficiency of 2.73 % at 7 cycles.

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A field-emission cathode based upon the increase in the number of allowed conductive energy states in the silicon monoxide (SiO) forbidden gap as well as the increase in the number of interfacial states by indium tin oxide (ITO) ion diffusion into the SiO layer and silicon ion diffusion into the ITO layer while deposition is verified experimentally for the first time. This relatively low-cost electron emitter consists of an ITO layer sputtered on Pyrex glass, followed by an E-beam-evaporated silicon monoxide layer. The emitting layer is gold, deposited on the top of the silicon monoxide. Using ITO as a ground plate, instead of other previously published materials, a significant electron emission enhancement occurred.

PN photodiodes, as an alternative form of photodetectors, is based on carrier production in the high-field junction region, and it has a response time considerably faster than that of a photoconductor and is typically in the order of nanoseconds. Photodetectors operating in the short wavelength ultraviolet (UV) region are important devices that can be used in various commercial and military applications. In the present work, we fabricated the p- GaN / n-Si heterojunction photodiode to observe the photoelectric effects. From the results, the current–voltage characteristics of the device show the typical rectifying behavior of heterojunctions. The UV photocurrent measurement was performed using an Hg -lamp under a reverse bias.

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