High-Performance and Low-Cost Aluminum Zinc Oxide and Gallium Zinc Oxide Electrodes for Liquid Crystal Displays

The majority of electro-optical devices use transparent conductive oxide (TCO) electrodes such as indium tin oxide (ITO) in their structure. In this study, we manufactured aluminum zinc oxide (AZO) and gallium zinc oxide (GZO) TCO films on glass substrates and demonstrate suitability of these materials for application as transparent electrodes of liquid crystal displays (LCD). We have established a deposition process for the fabrication of AZO and GZO coated glass substrates with average transmittance of 93% and 92% in the visible spectrum, and the sheet resistivity without annealing of ∼120 Ω/□. Using photolithographic patterning and wet etching of AZO and GZO films, we have successfully fabricated laboratory prototypes of twisted nematic, vertical alignment, in-plane switching, and fringe-field switching LCDs. The electro-optical performance of AZO and GZO prototypes is comparable to those of the ITO prototypes of identical design. The AZO and GZO have demonstrated great potential to compete with ITO as low-cost TCOs for display applications. Our findings validated by numerical analyses will be useful for the development of TCOs alternative for display and other optical or electro-optical applications.