Electroluminescence from TiO2/p+-Si heterostructure

Titanium films sputtered on heavily boron-doped (p(+)) silicon substrates were thermally oxidized to form electroluminescent TiO2/p(+)-Si heterostructures. The electroluminescence (EL) features a broad spectrum covering red, green, and blue regions. We believe that in TiO2 recombinations between electrons at oxygen-vacancy-related energy levels and holes in the valence band result in the EL. Furthermore, the EL mechanism has been explained in terms of the energy band diagram of the TiO2/p(+)-Si heterostructure, which possesses an intermediate ultrathin SiOx layer revealed by high resolution transmission microscopy.