Diode having vertical structure

A light emitting device, comprising:

• a metal layer;
• a reflective conductive layer on the metal layer, the reflective conductive layer serving as a first electrode;
• a first-type GaN-based layer having a first surface on the reflective conductive layer;
• an active layer on the first-type GaN-based layer, the active layer comprising AlInGaN;
• a second-type GaN-based layer on the active layer;
• a second electrode on a second surface of the second-type GaN-based layer;
• and
• a pad on the second electrode,
• wherein the second surface is opposite the first surface with respect to the active layer,
• wherein the reflective conductive layer is configured such that the reflective conductive layer reflects light from the active layer back through the first surface, and
• wherein a thickness of the pad is about 0.5 μm or higher.