A semiconductor device having light-emitting diodes (LEDs) formed on a concave textured substrate is provided. A substrate is patterned and etched to form recesses. A separation layer is formed along the bottom of the recesses. An LED structure is formed along the sidewalls and, optionally, along the surface of the substrate between adjacent recesses. In these embodiments, the surface area of the LED structure is increased as compared to a planar surface. In another embodiment, the LED structure is formed within the recesses such that the bottom contact layer is non-conformal to the topology of the recesses. In these embodiments, the recesses in a silicon substrate result in a cubic structure in the bottom contact layer, such as an n-GaN layer, which has a non-polar characteristic and exhibits higher external quantum efficiency.