Density functional theory study of dopants in polycrystalline TiO2
Density functional theory study of dopants in polycrystalline TiO2
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DOI：
10.1103/physrevb.83.205315
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发表时间：
2011-05-24
影响因子：
3.7
通讯作者：
Elsaesser, Christian
中科院分区：
文献类型：
--
作者：
Koerner, Wolfgang;Elsaesser, Christian
我们提出了一个密度泛函理论（DFT）的研究掺杂金红石和金红石型TiO 2中，我们调查的影响，晶界上的物理原子缺陷。主要目标是获得关于由氧空位、钛间隙、阳离子掺杂剂Nb、Al和Ga以及阴离子掺杂剂N在电子带隙中产生的缺陷能级的位置的信息，所述电子带隙考虑到TiO 2作为透明导电氧化物（TCO）的应用或其在多相催化中的用途。由于已知的DFT的局部密度近似（LDA）的缺陷，以产生准确的值为绝缘体，如TiO 2的带隙能量，自相互作用校正（SIC）的LDA。我们的研究的主要结果是，晶界影响的缺陷形成能，以及掺杂诱导的电子能级的位置和形状显着相对于单晶。根据我们的研究，Nb掺杂可能导致n-导电TiO 2，而掺杂N，Al或Ga是没有希望的，以实现p-导电TiO 2。此外，我们的结果可以解释的增加，在光电导的TiO 2：N和无色的TiO 2：Al。
We present a density functional theory (DFT) study of doped rutile and anatase TiO2 in which we investigate the impact of grain boundaries on the physics of atomic defects. The main goal is to obtain information about the positions of the defect levels generated by an oxygen vacancy, a titanium interstitial, cation dopants Nb, Al, and Ga, and an anion dopant N in the electronic band gap having in mind the application of TiO2 as a transparent conducting oxide (TCO) or its use in heterogeneous catalysis. Due to the known deficiency of the local density approximation (LDA) of DFT to yield accurate values for band gap energies for insulators such as TiO2, a self-interaction correction (SIC) to the LDA is employed. The main result of our study is that grain boundaries do affect the defect formation energies as well as the position and shape of the dopant-induced electronic energy levels significantly with respect to the single crystal. According to our study Nb doping may lead to n-conducting TiO2 whereas doping with N, Al, or Ga is not promising in order to achieve p-conducting TiO2. Furthermore an increase in the photoconductivity of TiO2: N and the colorlessness of TiO2:Al may be explained by our results.