Gallium nitride surface quantum wells

Surface quantum-well emission has been observed from GaN-capped AlGaN∕GaN heterostructures grown by metalorganic chemical vapor deposition. The GaN cap, which forms the surface quantum well, is confined on one side by the vacuum level and on the other side by the AlGaN barrier layer. Photoluminescence at room temperature and cathodoluminescence studies show a strong emission peak corresponding to the lowest bound state of the surface quantum well and a correlation was made to the shift in surface quantum-well emission energy and the thickness of the GaN capping layer, which was varied from ∼15to40Å. The efficient surface quantum-well emission is indicative of low surface recombination velocities even without any surface passivation.