▎ 摘　　要

NOVELTY - The method involves growing (S104) a dielectric layer on the surface of the sample after forming the graphene transparent electrode, and etching (S105) the dielectric layer. A graphene protective layer is formed on the contact layer except for the area corresponding to the lower electrode, the graphene transparent electrode and the sidewall of the mesa structure. The dielectric layer is etched on the graphene transparent electrode to obtain the area corresponding to the upper electrode. An upper electrode is prepared on the corresponding area of the upper electrode on the graphene transparent electrode to obtain an ultraviolet photodiode. USE - Method for preparing ultraviolet photodiodes. ADVANTAGE - The electric field distribution is expanded under the entire photon detection active area, which greatly improves the detection efficiency of the ultraviolet photodiode. DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart illustrating a method for preparing ultraviolet photodiodes. (Drawing includes non-English language text) Step for preparing first contact layer and mesa structure on substrate (S101) Step for preparing lower electrode on first contact layer except for mesa structure to form first sample (S102) Step for transferring prepared multilayer graphene film to surface of first sample (S103) Step for growing first dielectric layer on surface of first sample (S104) Step for etching first dielectric layer on graphene transparent electrode (S105)