Authors: Aifei Pan Wenjun Wang Xuesong Mei Qijing Lin Jianlei Cui Kedian Wang Zhaoyang Zhai
Publish Date: 2017/03/17
Volume: 123, Issue: 4, Pages: 253-
Abstract
This paper presents the preparation of different kinds of titanium oxide fractal structures on the surface of titanium by inverse pulsed laser deposition IPLD in air and water In air twodimensional fractal structures are obtained with a low pulse energy However their branches units are aggregated and nanoscale branches disappear due to the high substrate temperature causing the low fractal dimension of structure When a higher laser energy is applied the preformed deposited material forms a porous film which reduces heat transfer from substrate Therefore threedimensional and onedimensional fractal structures with nanoscale branches on the topside of the film can be obtained Then the desired twodimensional fractal structures with nanobranches are obtained in water due to the waterinduced rapid cooling of substrate temperature and plasma shock waveinduced particle’s expansion along the surface of substrate Meanwhile the asymmetry of fractal structure units analyzed by diffusion limited aggregation DLA model is caused by the difference of the distance between the initial deposited particles In addition when the pulse energy goes up to 111 mJ the branches of twodimensional fractal structure units are also aggregated and form isolated particles The idea about modification of substrate temperature and water can guide the preparation of the desired titanium oxide fractal structures in pulsed laser deposition PLD which is also applicable to other materials
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