双层Nb掺杂TiO_2薄膜的导电性研究

Growth and Conductivity Enhancement of Nb-Doped TiO_2 Bi-Layer

采用射频磁控溅射的方法通过改变氧分压和基体温度在非晶超白玻璃上沉积了一系列Nb掺杂Ti O_2薄膜,富氧状态下的薄膜为锐钛矿相且绝缘,少氧状态下的薄膜为金红石相但电阻率太大。采用双层膜的结构,首先将在非晶基体上沉积一系列在富氧状态下得到的的锐钛矿相Nb掺杂Ti O_2薄膜为种子层,然后在种子层上外延一层少氧状态下的Nb掺杂Ti O2薄膜为表层,得到的薄膜具有良好的导电性。

The Nb-doped Ti O2bi-layers were synthesizedby RF reactive magnetron sputtering on substrate of super white glass. The impact of the growth conditions,including but not limited to the oxygen partial pressure,substrate temperature and sputtering time,on the phase structures and resistivity of the bi-layer was investigated with Xray diffraction and four point probe resistivity measurement. The results show that depending on the O2 partial pressure,the Nb-doped Ti O2bi-layers display good conductivity. To be specific,at a high O2 partial pressure,the highly insulating anatase-phased layer was synthesized;whereas at a low O2 partial pressure,the rutile-phased layer with a large resistivity was deposited. The Nb-doped Ti O2bi-layer,consisting of the anatase-phased ＂seed＂layer on amorphous substrate and the epitaxially grown,rutile-phased top layer was found to possess a fairly low resistivity（1. 89× 10- 3Ω·cm）. Possible mechanisms responsible for the resistivity reduction were tentatively discussed.