Nitride LEDs and Lasers with Buried Tunnel Junctions

Traditionally, Nitride semiconductors have suffered from poor p-type conductivity, requiring Mg activation by removing hydrogen from grown layers either through thermal annealing or electron irradiation. This requirement restricts the growth of buried p-type layers. Here, we report structures obtained using a Hydrogen-free growth technique - plasma assisted molecular beam epitaxy. Using this method, top and bottom tunnel junctions are realized for top and bottom contacts to traditional Ga-polar devices. Advantages of using both constructions are discussed. The efficiency of the bottom-tunnel junction design is presented through realization of a stable laser diode operating at room temperature. Further work needed to improve tunnel junction performance as well as optical mode confinement to fully benefit from this design is outlined.