Novel growth of GaN with low dislocation density for UV lasers

For realization of UV semiconductor laser using III-nitride materials there are couple of breakthroughs to be overcome. Quantum dots formation in quasi-lattice matched system, reduction of dislocation density, formation of highly doped p-type layer and ohmic contact to the layer are typical examples. Recently we have developed couple of techniques to overcome those subjects. A typical example is a quantum dot formation on a surface of quasi-lattice matched or lattice matched substrate using atomic anti-surfactant which acts as atomic nano mask and effective reduction of dislocation density using the atomic nano mask. In this paper, recent experimental results focused on quantum dots formation in quasi-lattice matched system and effective reduction of dislocation density of GaN using the atomic nano mask on the substrate surface are reported.