It was noted that electroluminescence from TiO2/p+-Si heterostructure-based devices could be significantly enhanced by prior treatment of TiO2 films in argon plasma. It was found that the Ar-plasma treatment introduced excess oxygen vacancies within a certain depth of TiO2 films. The increase in the concentration of oxygen vacancies leads to the enhancement of electroluminescence from TiO2/p+-Si heterostructure-based devices because oxygen vacancies were the light-emitting centers. This work demonstrated the use of defect engineering to improve the performance of oxide-based opto-electronic devices.

Enhancement of Electroluminescence from TiO2/p+-Si Heterostructure-Based Devices through Engineering of Oxygen Vacancies in TiO2. Zhang, Y., Ma, X., Chen, P., Li, D., Pi, X., Yang, D., Coleman, P.G.: Applied Physics Letters, 2009, 95[25], 252102