利用磁控溅射在重掺硼硅(p+-Si)衬底上分别沉积TiO2薄膜和掺硼的TiO2(TiO2∶B)薄膜,并经过氧气氛下600 ℃热处理,由此形成相应的TiO2/p+-Si和TiO2∶B/p+-Si异质结.与TiO2/p+-Si异质结器件相比,TiO2∶B/p+-Si异质结器件的电致发光有明显的增强.分析认为：TiO2∶B薄膜经过热处理后,B原子进入TiO2晶格的间隙位,引入了额外的氧空位,而氧空位是TiO2/p+-Si异质结器件电致发光的发光中心,所以上述由B掺杂引起的氧空位浓度的增加是TiO2∶B/p+-Si异质结器件电致发光增强的原因.

TiO2/p+-Si and TiO2∶B/p+-Si heterostructures were formed by sputtering TiO2 films and boron-doped TiO2 (TiO2∶B) films on heavily boron-doped silicon (p+-Si) substrates,respectively,followed by annealing at 600 ℃ in O2 ambient.In contrast with the TiO2/p+-Si heterostructured devices,the TiO2∶B/p+-Si counterpart exhibits markedly enhanced electroluminescence (EL).It is derived that the doped B atoms in TiO2∶B films enter into the interstitial sites of TiO2 lattice after annealing at high temperature,which introduces excess oxygen vacancies.The increase of the concentration of oxygen vacancies due to B-doping leads to the enhancement of EL from the TiO2∶B/p+-Si heterostructured devices because oxygen vacancies are the light-emitting centers of the TiO2/p+-Si heterostructured devices.