Spacer LED architecture for high efficiency micro LED displays

A method of forming an optical device, the method comprising the steps of:

• forming a mesa, the mesa comprising an active layer configured to emit light from a first light emitting surface of the mesa when subjected to an electrical current, the mesa further comprising a second surface opposite the first light emitting surface and substantially vertical sidewalls, wherein the sidewalls of the mesa are roughened;
• forming spacers on the mesa sidewalls, the spacers being formed from a first electrically insulating optically transparent material, and having an internal face facing the mesa sidewalls, and an opposing external face, wherein the external faces of the spacers are straight sided and angled outward away from the mesa sidewalls;
• depositing a first layer of transparent electrically conducting material on the second light emitting surface of the mesa, the transparent electrically conducting material having an internal face facing the second surface of the mesa, and an opposing external face, wherein the external face of the first layer of transparent, electrically conducting material is substantially convex, and the external face of the first layer of transparent, electrically conducting material has a radius of curvature of between 1 and 1.5 microns;
• forming a second layer of transparent, electrically conducting material on the first light emitting surface of the mesa;
• and
• depositing a layer of reflective electrically conducting material over the transparent electrically conducting material and external faces of the spacers.