Reduction of threading dislocation density in Al XGa 1− XN grown on periodically grooved substrates

Abstract

We proposed a heteroepitaxial lateral overgrowth technique using periodically grooved substrates to prepare a GaN single crystal with low dislocation density. By this technique, GaN single crystals have been grown without a selective growth mask or GaN single crystal seeds. Moreover, the AlGaN single crystal, which is important for optoelectronic devices in the UV region, can also be grown using this technique. The reduction of the threading dislocation density in Al X Ga 1− X N single crystals grown on periodically grooved substrates was confirmed by transmission electron microscopy.