Electron doping turns semiconductors conductive even when they have wide fundamental band gaps. The degenerate electron gas in the lowest conduction-band states, e.g., of a transparent conducting oxide, drastically modifies the Coulomb interaction between the electrons and, hence, the optical properties close to the absorption edge. We describe these effects by developing an ab initio technique...

The spin or nonspin state of electrons in W-doped anatase TiO2 is very difficult to judge experimentally because of characterization method limitations. Hence, the effect on the microscopic mechanism underlying the visible-light effect of W-doped anatase TiO2 through the consideration of electronic spin or no-spin states is still unknown. To solve this problem, we establish supercell models of ...

Ambipolar conduction in transistors using solution grown InAs nanowires with Cd doping " (2007).

We identify two general types of electronic behaviors for transition-metal impurities that introduce excess electrons in oxides. (i) The dopants introduce resonant states inside the host conduction band and produce free electrons; (ii) the dopants introduce a deep gap state that carries a magnetic moment. By combining electronic structure calculations, thermodynamic simulations, and percolation...