Kinetic Monte Carlo Simulations of Defects in Anatase Titanium Dioxide

Anatase titanium dioxide is a highly promising material for memristors and photocatalysis. Multiple electronic transport processes are known to be influenced by defects in nanoscale anatase. Hence, in this study, we examine charge transport due to defects with respect to the fabrication of nm-thin TiO2-films via kinetic Monte Carlo (kMC). A compact kMC-model for MOS and MOM-structures comprising TiO2 was parametrized by the electronic properties of TiO$_{2}$ in agreement with literature, in particular spectroscopic studies and DFT calculations on defects in anatase. KMC-simulations of MOS-structures were refined, for the first time, by separate drift-diffusion-simulations on the band bending in p+-Si substrates as well as by barrier heights adjusted for the Fermi-level pinning effect. Referring to the impact of specific TiO2-film growth methods and post-growth treatments on the parameters for defect energies, in particular, electrical jV-characteristics of material stacks fabricated by PVD and CVD methods, as reported in literature, were reproduced computationally at high accuracy. Thus, conclusions on the dependence of electron trap levels in anatase in dependence of the sample processing could be drawn from this kMC-based computational analysis, attributing defects in TiO2 to shallow titanium interstitials Tiint or deep oxygen vacancies VO depending on the fabrication methods.     «

Anatase titanium dioxide is a highly promising material for memristors and photocatalysis. Multiple electronic transport processes are known to be influenced by defects in nanoscale anatase. Hence, in this study, we examine charge transport due to defects with respect to the fabrication of nm-thin TiO2-films via kinetic Monte Carlo (kMC). A compact kMC-model for MOS and MOM-structures comprising TiO2 was parametrized by the electronic properties of TiO$_{2}$ in agreement with literature, in part...     »