Pulsed laser deposition of ZnO honeycomb structures on metal catalyst prepatterned Si substrates

Honeycomb structures with controllable size are of great interest for many potential applications such as containers for microencapsulating and controlled delivery, gas sensors, catalysis and photonic crystals and devices. A ZnO honeycomb structure was successfully fabricated on metal prepatterned Si substrates by the nanosphere lithography method combined with the pulsed laser deposition (PLD) technique. SEM images show that a Pt template gives rise to the regular ZnO honeycomb structure which has the same cell size as the diameter of polystyrene (PS) spheres; a Au template also leads to honeycomb structure but the average cell size is smaller than the diameter of PS spheres; while Ag fails to generate a ZnO honeycomb structure. The different ZnO patterns are related to the morphology and distribution of the metal nanoparticles when processed at 600 deg. C in a PLD vacuum chamber. The growth mechanism of a ZnO honeycomb structure is attributed to the catalysis of liquid-phase metal nanoparticles. X-ray diffraction measurements indicate that ZnO on all metal templates have the (0 0 2) preferential orientation. The photoluminescence properties of the ZnO patterns were also examined and compared. Such a method can be extended to produce honeycomb structures of other materials with controlled cell size and periodicity.