Growth And Characterization Of Rutile Tio2 Nanostructures Synthesized By Chemical Bath Deposition For Uv Photodetector Applications

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Date
2015-12
Authors
Abbas, Mohammed Selman
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Universiti Sains Malaysia
Abstract
In this project, nanostructured rutile-phase titanium dioxide (TiO2) was successfully fabricated using the chemical bath deposition (CBD) method. This study aimed to fabricate uniform and high-quality rutile TiO2 nanostructure (Ns) using a low-cost technique and to determine the optimum conditions for uniform rutile TiO2 Ns development grown using the CBD method on various substrates, such as p-type Si (111), c-plane sapphire (Al2O3), FTO-coated glass (FTO glass), glass and quartz. Furthermore, the effects of substrate type and growth conditions [pH media, time duration, annealing treatment, growth temperature, and variations in precursor concentration (TiCl3 solution)] on the morphological, structural, and optical characterizations of rutile Ns were correspondingly examined. First, glass substrates were selected as a low-cost substrate to study the influence of deposition temperature on the rutile TiO2 Ns preparation.The optimum growth conditions were subsequently used to studythe effect of substrates on rutile preparation. TiO2 seed layer has been prepared on the substrates via a radio frequency reactive magnetron sputtering system prior to rutile TiO2 Ns growth. Second, the sample of rutile Ns grown on a Si substrate was determined as the optimal sample. Therefore, to elucidate the influence of preparation conditions on the characteristics of rutile TiO2 Ns, the effects of several parameters, that were mentioned above, were investigated. All of the Si substrates were seeded with a TiO2 seed layer (the TiO2 seed layer was also examined in this research). Based on the observations and results analyses of the growth conditions, the sample prepared at a temperature of 55 °C, pH of 0.7, duration of growth of 3 h, concentration of TiCl3 solution of 4 mM, and annealing temperature of 550 °C produced the optimal structural, morphological, and optical properties with the highest (110) XRD peak intensity. In addition, the Raman spectra confirmed the rutile crystal phase of TiO2, and the highest PL ultraviolet (UV) intensity was attributed to the good quality of TiO2 nanorods with few defects. These results indicate that the optimized growth conditions yield very high quality TiO2 Ns on p-type (111)-oriented Si substrates. Finally, the parameters were optimized to control the crystal structure and surface morphology and the optical characterizations of rutile TiO2 Ns. The films with optimal properties were then selected to fabricate highly sensitive, fast-responding, and rapidly recovering p-n heterojunction photodiode and metal-semiconductor-metal (MSM) photodiode. The p-n heterojunction photodiode exhibited higher photoresponse, quantum efficiency, and sensitivity as compared to the MSM photodiodes.
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Nanostructure
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