Oxygen defect induced photoluminescence of HfO2 thin films

Amorphous HfO2 films prepared by e-beam deposition exhibited room-temperature photoluminescence (PL) in the visible range, i.e., at ∼620 and 700nm, due to oxygen vacancies involved during deposition. This PL can be enhanced by two orders in intensity by crystallizing the amorphous films in flowing argon, where a large amount of oxygen vacancies were introduced, and can be diminished by removal of the oxygen vacancies by annealing HfO2 films in oxygen. This study could help understand the defect-property relationship and provides ways to tune the PL property of HfO2 films.