Abstract: An ultraviolet light-emitting diode is disclosed. The ultraviolet light-emitting diode includes a transparent substrate, an ultraviolet illuminant epitaxial structure, and a transparent structure. The transparent substrate includes a first surface and a second surface which are opposite to each other, and a plurality of side surfaces surrounding and disposed between the first surface and the second surface. The ultraviolet illuminant epitaxial structure is disposed on the first surface of the transparent substrate. The transparent structure has a light-entering surface and a light-exiting surface which are opposite to each other. The light-entering surface of the transparent structure is adjacent to the second surface of the transparent substrate, and a refractive index of the transparent structure is between a refractive index of the transparent substrate and a refractive index of air.

Abstract: An ultraviolet light-emitting diode includes a transparent substrate and an ultraviolet illuminant epitaxial structure. The ultraviolet illuminant epitaxial structure includes an N-type semiconductor layer which is disposed on the transparent substrate and comprised of a first portion and a second portion. The first portion of the N-type semiconductor layer includes a light-emitting layer disposed thereon, a P-type semiconductor layer on the light emitting layer, and a P-type contact layer disposed on the P-type semiconductor layer. The second portion of the N-type semiconductor layer includes an N-type semiconductor film disposed thereon and separated from the light-emitting layer. A band gap of the N-type semiconductor film is smaller than a band gap of the light-emitting layer. The N-type contact is disposed on the N-type semiconductor film. The P-type contact is disposed on the P-type contact layer.

Abstract: An ultraviolet light-emitting diode is disclosed. The ultraviolet light-emitting diode includes a transparent substrate, an ultraviolet illuminant epitaxial structure, and a transparent structure. The transparent substrate includes a first surface and a second surface which are opposite to each other, and a plurality of side surfaces surrounding and disposed between the first surface and the second surface. The ultraviolet illuminant epitaxial structure is disposed on the first surface of the transparent substrate. The transparent structure has a light-entering surface and a light-exiting surface which are opposite to each other. The light-entering surface of the transparent structure is adjacent to the second surface of the transparent substrate, and a refractive index of the transparent structure is between a refractive index of the transparent substrate and a refractive index of air.