Optimization of UV luminescence from ZnO thin film: A combined effect of Al concave arrays and Al2O3 coating

A synergistic effect of surface plasmons (SPs) and surface passivation on ZnO thin film optical performance was studied. The ZnO thin film of thickness of ca. 40 nm was deposited on Al concave arrays with a period (Dc) of about 125, 252, and 340 nm. Next, the Al2O3 coating thickness was tested with respect to UV light enhancement. About 20-fold enhancement of the UV emission was achieved upon simultaneous application of Al concave array with Dc ≈ 340 nm and 10 nm thick Al2O3 coating. Moreover, it was found that the Al concave array with Dc of ca. 125 nm does not sustain the SP resonance in UV region.