Micro-nano device and preparation method thereof

The invention relates to a micro-nano device and a preparation method thereof. The micro-nano device comprises: a substrate; a ZnO nano layer deposited on the substrate; graphene quantum dots synthesized in a self-assembling manner on the ZnO nano layer; and nano Au colloid which is synthesized, by further carrying out catalytic degradation, on the substrate with the ZnO nano layer with the graphene quantum dots synthesized in the self-assembling manner. The micro-nano device is excellent in performance and low in cost, and can be applied to water resources with rhodamine pollution.