Here　we　report　a　novel　hybrid　structure　composing　of　microsphere　array　(MA),　Al　nanoparticles　(Al-NPs),　ZnO　thin　film　(luminescence　layer),　Au　nanoparticles　(Au-NPs)　and　substrate　(sapphire)　for　ultraviolet　(UV)　luminescence　enhancement　of　planar　wide　bandgap　semiconductor　film.　The　plasmonic　sandwich　structure　of　Al-NPs/ZnO/Au-NPs　boosts　the　hot　electron　state　density　in　the　conduction　band　by　electron　trapping　from　deep-defect　level　of　ZnO　and　localized　surface　plasmon　resonances　(LSPRs)　coupling　around　dual　metallic　NPs.　enhancing　UV　emission　and　suppressing　visible　emission　efficiently.　The　dielectric　microsphere　array　capping　on　the　plasmonic　sandwich　structure　further　increases　UV　emission　intensity　via　photonic　nanojets　optical　whispering-gallery　modes　(WGMs).　and　directional　antenna　effect,　by　which　the　interaction　between　photon　and　exciton　is　strengthened.　The　contribution　of　microsphere　cavity　coupling　with　LSPRs　to　UV　luminescence　enhancement　is　therefore　revealed.　The　maximum　enhancement　ratio　of　up　to　two　orders　of　magnitude　(similar　to　250-fold)　is　achieved　by　the　optimized　5.06-mu　m-diameter-MA/Al-NPs/ZnO/Au-NPs/sapphire　structure　and　the　UV　emission　is　highly　directional　with　a　divergent　angle　of　similar　to　5　degrees.　The　present　work　provides　a　simple　and　easily-prepared　structure　incorporating　optical　WGMs　and　LSPRs　to　manipulate　UV　luminescence　of　planar　wide-bandgap　semiconductors　for　potential　optoelectronic　applications.　(C)　2019　Optical　Society　of　America　under　the　terms　of　the　OSA　Open　Access　Publishing　Agreement