Using a solution crystal growth method to grow arrays of aligned, individually distinct, single-crystalline TiO2 nanoneedles within nanocavities

The arrays of single, aligned TiO2 nanoneedles within nanocavities were fabricated using a solution crystal growth process under an applied electric field. The TiO2 underlayer in rutile phase facilitated the growth of vertical TiO2 needles in the nanocavities across the photoresist layer homogeneously. It was also observed that the values of pHi and the ratio R both affected the morphology of the TiO 2 nanoneedles. It was shown that when the ratio R was over 300, the value of the pH rose quickly because of decomposition of urea, which led to increased precipitation in the aqueous solution and a decreased deposition as the aqueous solutions became supersaturated with TiO2.