TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The molar ratio of zinc ion, hexamethylenetetraamine and water is 0.02-2:0.02-2:1000. Several zinc oxide nanorod thin film growing solutions are prepared, and base plate is sequentially placed in one of the solutions for time fractions proportional to a number of the solutions. One zinc oxide nanorod thin film growing solution is prepared and base plate is placed in the zinc oxide nanorod thin film growing solution to allow the zinc oxide seed layer to grow for growing time. The base plate is made of a material chosen from glass, quartz, single crystal silicon, polycrystalline silicon, sapphire, polyethylene terephthalate, acrylate and polyimide. Zinc ion of zinc oxide nanorod thin film growing solution is provided by a material chosen from zinc acetate, zinc bromide, zinc chloride, zinc fluoride, zinc iodide, zinc sulfide, zinc sulfate and zinc nitrate. Zinc oxide seed layer is formed on the base plate by sol-gel method. Each crystal of zinc oxide seed layer has grain size of 5-100 nm, preferably 20 nm. Preferred Method: A sol-gel solution for making zinc oxide seed layer is prepared. The sol-gel solution comprises zinc ion, 2-methoxyethanol and monoethanolamine in molar ratio of 1:10-40:1. The sol-gel solution is applied on the base plate and the base plate is soft baked at 100 degrees C for 10 minutes, sintered at 200 degrees C for 10 minutes and then annealed at 200-800 degrees C to form the zinc oxide seed layer. The base plate on which the zinc oxide seed layer is formed is annealed at 400 degrees C. The zinc ion concentration of zinc oxide nanorod thin film growing solution is 0.05 M. The zinc oxide seed layer is allowed to grow into the zinc oxide nanorod thin film in the zinc oxide nanorod thin film growing solution at 75 degrees C for 6 hours. The zinc oxide seed layer is formed on the base plate by a sputtering method. The sputtering method is performed at oxygen flow rate of 30 sccm, argon flow rate of 8 sccm, background pressure of 5x 10-6 torr, working pressure of 15 mtorr, RF power of 150 W, base plate temperature of room temperature and sputtering time of 5 minutes. The base plate is kept at room temperature. The zinc oxide seed layer is formed on the base plate by free dip coating, spraying, organic chemical vapor deposition and laser ablation. The zinc oxide nanorod thin film has refractive index of more than 1.74.