Calculation of electronic density of states induced by impurities in TiO2 quantum dots -: art. no. 153313

We have theoretically calculated and analyzed the electronic density of states (DOS) in crystalline TiO2 nanoparticles in air (or vacuum) affected by the presence of impurities near the particle surface. The effect of temperature has been incorporated by changing the permittivity value of the quantum dot, in accordance with reported dependences. Our model is described by a truly three-dimensional effective mass Hamiltonian with a realistic finite steplike confining potential and the Coulomb terms, including dielectric mismatch effects. The presence of impurities in nanometer systems naturally induces band tailing with details depending on the dielectric response of involved media. Our calculations predict a dependence of the DOS on temperature. Moreover, a high degree of electronic density delocalization within the quantum dots is found, which has important implications on developing transport models.