Preparation and Characterization of ZnO: In Transparent Conductor by Low Cost Dip Coating Technique

• 作者: M. Abdel Rafea Sh. El Yamny
• 来源期刊: 现代物理(英文)
• 学科: 医学
• 关键词: ZnO:In TCO DIP COATING OPTICAL and Electrical Properties
• 年，卷（期）: 2012,（9）
• 页码范围: 1060-1069
• 页数: 10页
• 分类号: R73

摘要

Transparent conducting oxide (TCO) based on indium doped zinc oxide films in the nano scale were successfully prepared using combination between dip coating and thermal decomposition process. Structural investigations confirm the polycrystalline ZnO hexagonal wurtzite phase grown along the c-axis with nano crystallite size about 10 nm. Morphology investigation shows that ZnO films consist of fine grains of average size 40 nm. This indicates that each grain contains several crystallites with different orientations. Cross sectional image presents good adhesion of the films with the substrate and the film thickness has been determined. Compositional analysis detects the indium content in the host ZnO matrix, the In/Zn ratio is close to the calculated concentration ratios of the precursor. The optical transmittance shows that the films are transparent in the UV and VIS-IR spectral region and interference fringes were observed to be thickness dependent. Preparation parameters were investigated and optimized such as dipping rate, number of deposition cycles, precursor concentration, annealing process and In/Zn ratio. Optimization process was investigated for low resistivity, high optical spectral window transmission and easy preparation process. Dipping rate in the range 2 - 38 mm/s is the most suitable range for good film quality while dipping rate range 30 - 38 mm/s produces thicker films in lower deposition cycles. The higher dipping rate produces films with lower transparency (milky films) while the small deposition rate rate requires large number of deposition cycles in order to increase the thickness. Besides, the higher dipping rate reflects lower resistivity of the deposited films. Precursor molar concentration was observed to have an essential effect on the film thickness, film quality and transparency. Lower precursor concentration requires also large number of deposition cycles for thickening the films. The higher concentration results also milky films (high scattering process by powder film). Precursor conc