Seed-free growth of strongly UV emitting self-supported hybrid ZnO nanowire/graphite membranes

•Hybrid ZnO nanowire/graphite self-supported membranes were grown by vapor transport.•Long entangled ZnO nanowires grew on seed/catalyst-free compacted graphite flakes.•Hybrid membranes exhibited very strong UV and negligible visible emissions.•Substrate holder orientation had key role for membrane growth & properties.•Hybrid membranes spontaneously detached from the substrate holder during cooling.