Light emitting diode and fabrication method thereof
A light-emitting diode includes from bottom to up: a substrate; a light-emitting epitaxial layer laminated by semiconductor material layers over the substrate; a current spreading layer doped with conductive metal nanomaterial groups over the light-emitting epitaxial layer; and metal nanomaterial groups with high visible light transmittance over the current spreading layer. The conductive metal nanomaterial groups dispersed inside the ITO current spreading layer can reduce horizontal resistance of the current spreading layer and improve horizontal spreading uniformity of current; and metal nanomaterial groups with high visible light transmittance are distributed over the upper surface of the current expansion layer for roughening and increasing light extract efficiency.
1. A fabrication method of a light-emitting diode, the method comprising:
(1) providing a substrate; growing a light-emitting epitaxial layer including semiconductor material layers via epitaxial growth;
(2) forming a current spreading layer doped with conductive metals over the light-emitting epitaxial layer;
(3) forming metal layers over the current spreading layer;
(4) performing a one-time annealing thermal treatment; wherein:
the current spreading layer comprises an ITO current spreading layer;
the conductive metals comprise conductive Ag metals;
the metal layers comprise an Al metal layer; and
the ITO current spreading layer doped with conductive Ag metal is formed by simultaneous magnetron sputtering, and the Al metal layer is formed by electron beam evaporation.
2. The fabrication method of claim 1 , wherein, after the annealing thermal treatment, the Ag metal is oxidized into conductive Ag nanomaterial groups dispersed inside the ITO current spreading layer.
3. The fabrication method of claim 1 , wherein, after the annealing thermal treatment, the Al metal layer is oxidized into Al nanomaterial groups with discontinuous distribution.
4. The fabrication method of claim 1 , wherein the one-time annealing thermal treatment is under high temperature with continuous oxygen input during the annealing thermal treatment to fully oxide the doped Al and Ag metals simultaneously.
5. The fabrication method of claim 1 , wherein, the one-time annealing thermal treatment comprises fast aerobic annealing for 200-300 s under 550-600° C., and a 15-30 sccm oxygen intake.