Effect of Annealing Temperature on Liquid Crystal Alignment Using Ion-Beam Irradiated Gallium Tin Oxide as an Alignment Layer and Effective Liquid Crystal Switching in Twisted Nematic Mode

We investigated the effect of annealing temperature on liquid crystal (LC) alignment layers. LCs were homogeneously aligned to an ion beam (IB)-irradiated Gallium tin oxide film (GaSnO) at selected high annealing temperatures. To understand the mechanism of LC alignment, SEM and XPS were conducted. At high annealing temperatures, topographical and chemical modifications occurred on the surface. Consequently, the LC molecules were well aligned on the IB-irradiated GaSnO film. To confirm the possible utility of IB-irradiated GaSnO films as alternative LC alignment layers, the electro-optical performance of the new LC cells was tested by assessing the transmittance versus applied voltage and was compared with that of rubbed PI. The threshold voltage of the GaSnO-containing cell was similar to that of rubbed PI, while amplitude of switching voltage (ASV) of IB-irradiated GaSnO film was larger than that of rubbed PI. This indicated that the LC cell containing IB-irradiated GaSnO should effectively yield excellent color depth. Therefore, IB-irradiated GaSnO annealed at a high annealing temperature could be used an alternative alignment layer for the preparation of LC cells that exhibit stable and effective performance in LC applications.