One step growth of TiO2 crystal trees by atmospheric pressure plasma jet

Micro-scale TiO2 crystal trees were fabricated on quartz glass substrates via atmospheric pressure plasma jet (APPJ) from the mixture gas of titanium tetrachloride (TiCl4) vapor, argon and oxygen by one step. Small variations in deposition parameters have a dramatic effect on the structure of the deposits. The heights of these TiO2 trees vary from several micrometers to over one hundred micrometers. The high resolution transmission electron microscope of the TiO2 trees (HRTEM) clearly shows the lattice fringes, which serves as evidence that the TiO2 trees are quite crystalline. The X-ray diffraction (XRD) and the selected area diffraction (SAED) results confirm the composition of anatase and rutile phase of these TiO2 trees. This particular tree-like structure of TiO2 shows a superhydrophobicity with water contact angle as high as 170°.