Abstract: Described are LED devices and corresponding manufacturing techniques. In some embodiments, an LED device includes a first doped semiconductor layer, a second doped semiconductor layer having an opposite doping, and a two-dimensional (2D) array of light emitting cells. Each light emitting cell corresponds to a mesa of an individual pixel and includes at least one quantum well. The 2D array is located between the first doped semiconductor layer and the second doped semiconductor layer. The LED device further includes a flattening layer between the first doped semiconductor layer and the 2D array. The flattening layer comprises an undoped quantum barrier (QB) layer that completely covers sidewalls of each light emitting cell in the 2D array. The undoped QB layer quantum mechanically isolates the light emitting cells from each other. The flattening or undoped QB layer may also protect the light emitting cells against etch-induced defects during a mesa pixelation process.