Mesoporous GaN Made by Selective Area Sublimation for Efficient Light Emission on Si Substrate

Selective area sublimation of thin (≤0.3 μm) GaN‐on‐Si epitaxial layers through nanoholes of an incomplete monolayer of SixNy results in the formation of mesoporous GaN. This morphologic change from a two‐dimensional flat layer to a nanostructured material presents the unexpected property of a huge increase (more than three orders of magnitude) of the GaN band edge photoluminescence intensity. Furthermore, the integrated photoluminescence intensity of such mesoporous GaN layers is comparable to a high quality 3.5 μm‐thick GaN‐on‐sapphire epitaxial layer or a 350 μm‐thick GaN substrate. Different possible mechanisms are discussed to explain the origin of the strong improvement of the optical properties. Selective area sublimation of thin GaN‐on‐Si epitaxial layers through nanoholes of an incomplete monolayer of SixNy results in the formation of mesoporous GaN. This morphologic change from a 2‐dimensional flat layer to a nanostructured material presents the unexpected property of a huge increase (> 3 orders of magnitude) of the GaN band edge photoluminescence intensity.