ULTRAVIOLET AND VIOLET LIGHT-EMITTING GAN DIODES GROWN BY LOW-PRESSURE METALORGANIC CHEMICAL VAPOR-DEPOSITION

Both metal-insulator-semiconductor and p-n junction electroluminescence have been observed in thin-film, metalorganic chemical vapor deposition-grown GaN diodes thermally annealed in N2. UV radiation, peaking near 380 nm, is emitted when electrons are injected from the undoped, n-type material into the Mg-doped, p-type GaN. Violet light, peaking near 430 nm, is obtained by injecting electrons into p-type material from either n-type material or non-ohmic metal contacts. The present results support and extend earlier interpretations of the nature of the recombination centers in GaN.