The liquid crystal (LC) alignment characteristics of the solution-derived lanthanum-doped zinc oxide (La:ZnO) film with ion-beam (IB) irradiation were investigated as a function of curing temperature. The best LC alignment state with uniform and homogeneous alignment was achieved at a curing temperature of 300 °C. To observe the effect of the IB irradiation on the La:ZnO film, physical and chemical surface analyses were conducted. Atomic-force microscopy revealed that surface roughness was increased, and the leptokurtic surface was changed to a platykurtic surface after the IB irradiation. X-ray photoelectron spectroscopy showed the breakage of the metal–oxide bonds, which induced an increase of oxygen vacancies. This caused van der Waals force, which strongly anchored LC molecules to the La:ZnO film. These results indicated that uniform and homogeneous LC alignment with the solution-derived La:ZnO films was induced by physical and chemical surface modification due to the IB irradiation. Moreover, residual DC was characterized by a capacitance-voltage hysteresis curve and nearly zero hysteresis was achieved. Therefore, IB irradiation is a useful method to achieve uniform and homogenous LC alignment, and using it with the solution-derived La:ZnO film exhibited potential for high-quality LC applications.
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© 2018 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics