Nearly single-crystalline GaN light-emitting diodes on amorphous glass substrates

Single-crystalline GaN-based light-emitting diodes (s-LEDs) on crystalline sapphire wafers can provide point-like light sources with high conversion efficiency and long working lifetimes. Recently, s-LEDs on silicon wafers have been developed in efforts to overcome the size limitations of the sapphire substrate. However, to create larger, cheaper and efficient flat light sources, the fabrication of high-performance s-LEDs on amorphous glass substrates would be required, which remains a scientific challenge. Here, we report the fabrication of nearly single-crystalline GaN on amorphous glass substrates, in the form of pyramid arrays. This is achieved by high-temperature, predominant GaN growth on a site-confined nucleation layer with preferential polycrystalline morphology through local hetero-epitaxy. InGaN/GaN multiple-quantum wells formed on the GaN pyramid arrays exhibit a high internal quantum efficiency of 52%. LED arrays fabricated using these GaN pyramid arrays demonstrate reliable and stable area-type electroluminescent emission with a luminance of 600 cd m^-2.