Titanium Dioxide and Arsenic-Based III-V Semiconductor Nanostructure Materials for High Performance Photoelectric Devices


Student thesis: Doctoral Thesis

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Awarding Institution
Award date8 Jan 2021


Nanostructures with at least one dimensional between 1 to 100 nm, have attracted steadily growing interests due to their particular and fascinating properties, and applications better than their bulk counterparts. It is essential to obtain the ability to generate such minuscule structures for most of modern science and technologies. When such one‐dimensional nanoscale building blocks are ordered and rationally assembled into appropriate two‐ or three‐dimensional architectures, fundamental scientific opportunities will be provided for investigation into the dependence of size and dimensionality with respect to their collective optical, magnetic, and electronic properties. This thesis mainly introduce two kinds of one dimensional nanostructured materials: TiO2 nanotube and InGaAs nanowire. For TiO2 nanotube, we develop a template assisted method to assemble TiO2 nanotubes into large scale three dimensional arrays for further applications. By a simple sol-gel procedure, TiO2 nanotube can be prepared. By assembling PS nanospheres using LB method, a precursor template can be obtained for TiO2 nanotube arrays to assemble. After that, organometal halide perovskite (CH3NH3PbI3) solution can be filtrated into the 3D TiO2 nanotube arrays to achieve the solar cell devices with enhanced performance in power conversion efficiency compared to conventional combination method with perovskite and TiO2. Moreover, TiO2 nanotube arrays deposited on various substrates, hard or flexible, can be also obtained due to the advantages of our assembly method, which can be used for miscellaneous purposes in future practical applications.

Then for InGaAs nanowire, as our previous work has developed the two-step CVD method for growing high crystalline and less defect ternary nanowire for InGaAs, we have to fabricate the optoelectronic device based on it. Due to the tunable bandgap in the range of IR region, IR photodetector might be a good choice for this. Therefore we compare the performance of IR photodetector based on the InGaAs nanowire grown by the different methods: two step and single step CVD. Because of the good crystallinity of two-step grown nanowire, the device accordingly shows enhanced photosensing ability. Also, we explore the dependence of the In content and the performance of the devices and find the results improve with the increasing In content in the nanowire. Furthermore, InGaAs nanowire arrays fabricated by a contact printing method is also introduced here for more practical application in the photodetector area.

    Research areas

  • TiO2 Nanotube Arrays, Perovskite Solar Cells, Photoresist Templates, InGaAs, Nanowires, High mobility, Ultra-fast Photodetector, In-rich, Contact Printing Method, Photodetector