Loading...

Fabrication and Optimization of Transparent Conductive Aluminum-Doped Zinc Oxide Thin Films by Chemical Bath Deposition Method

Mohammadi, Sina | 2022

169 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55066 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Taghavinia, Nima; Abachi, Parvin
  7. Abstract:
  8. Zinc oxide is a wide band gap semiconductor material with wide applications as conductive oxides used in electro-optical devices. Thin films of doped zinc oxide (e.g. Al:ZnO, B:ZnO) are already used in thin-film solar cell technologies as electrodes. Chemical bath deposition (CBD) is a promising method for fabricating transparent and conductive ZnO layers at low temperatures (<100 °C) on nonconductive and temperature-sensitive substrates. Having a natural crystal habit, ZnO readily grows rod-like arrays when grown in an aqueous solution by CBD, posing challenges when attempting to deposit dense and conductive layers. The purpose of this study was to deposit dense and conductive zinc oxide layers doped with aluminum by chemical bath deposition using different aluminum precursors at different concentrations. Doping with Al(OH)3 precursor with a concentration of 3 mM due to insolubility in the chemical bath, Aluminum is most effectively incorporated by supplying Al gradually during the CBD process. By testing a variety of doping strategies, the strategy of keeping aluminum precursors in a chemical bath solution for 24 hours before the deposition was determined as the most optimized strategy. Deposition of dense aluminum-doped zinc oxide thin films with visible transparency > 85 % and resistivity down to 3.7 × 10-3 Ω.cm are achieved by the optimized dopant concentration and doping strategy in this study. In this method, the UV treatment replaced the heat treatment at temperatures above 250 °C, which allows the coating conditions at temperatures below 150 °C. The stability of electrical conductivity has always been a challenge for transparent oxide conductive layers. As a result, the samples were encapsulated at the end of the deposition process, which improved the stability of resistivity. A major accomplishment of the research is the fabrication and optimization of transparent conductive aluminum-doped zinc oxide thin films with suitable structural, morphological, electrical, and optical properties for photovoltaic applications
  9. Keywords:
  10. Solar Cells ; Zinc Oxide ; Aluminum Hydroxide ; Transparent Thin Conductive Layer ; Chemical Bath Deposition (CBD)

 Digital Object List

 Bookmark

No TOC