Semi-polar GaN LEDs on Si substrate

Growth of semi-polar （1-101）GaN has been attempted on a patterned （001） silicon substrate adopting selective area MOVPE. The growth was initiated on （111） facets of the Si, which had been prepared by anisotropy etching in a KOH solution. A uni- form semi-polar layer was achieved by coalescence of stripes. Since the growth was performed on facets, the surface was atomically fiat in AFM surface analyses. By using a high temperature grown A1N nucleation layer, we achieved low threading dislocation density at the top most surface. Moreover, by tilting the c-axis of the GaN on the Si substrate, the effect of the thermal expansion coefficient mismatch was much reduced. As the result, we achieved a crack free （1-101）GaN template on （001）Si. On the thus prepared （1-101）GaN, a GalnN/GaN LED was fabricated, which showed excellent performance with weak quantum confined Stark effect.