Transiently controlled emission from ZnO surface.

ABSTRACT

We report on a photon (∼3.08 eV equivalent to 402 nm) controlled optical emission from ZnO (101¯0). Under below band gap excitation (∼2.33 eV equivalent to ∼532 nm), significant photoluminescence (PL) overlapped with Raman response is observed. The broad PL consists of three bands (629 (A), 690 (B), and 751 (C) nm) attributed to the defects arising due to excess zinc and charged oxygen vacancy. By employing asecondexcitation source at 402 nm, we demonstrate about 50% reduction in the overall PL. We utilize the doubly positive oxygen vacancy state to control the PL emission while transiently reducing its density.