Optical and Structural Characterization of GaN Grown by MBE Using Indium as a Surfacant

In conclusion the structural andl optical characterisation of GaNIn epilayers have shown that only a small amount ofin is incorporated into the Ga sites making the layers to be considered as not pure isoelectronically doped. The In atoms presumably occupy interstitial positions in the crystal lattice concentrate on mosaic grain boundaries and have a tendency to form clusters. The In nucleation near structural defects, like e.g. nano-pits. may recover the lattice structure. increasing the integral PL intensity. Besides. like at conventional isoelectronic doping, local strains induced by the inhomogeneous In distribution may activate mechanisms of structure improvement. On the other hand. the possible occupation of interstitials by the In atoms can hardly be considered as a positive factor.