Morphology and Work Function of In, Ag, Mg, and Au Nano-Islands Grown on AlN(0001) Surface

The study revealed that the nature of the AlN (0001) surface could play a fundamental role in the growth mode of metals. In the case of silver (Ag) deposited on the AlN(0001) (2x2)-N-ad reconstructed surface, the growth mode was Volmer-Weber. Deposition of indium (In) on a contaminated AlN(0001) surface leads to the formation of a wetting layer, followed by a 3D growth mode. For magnesium (Mg), a wetting layer was observed on the clean and contaminated surface followed by a 2D growth mode. Finally, the Au case was the most interesting since on the contaminated surface and the (2x2)-N-ad reconstructed surface, the growth mode was 3D and 2D, respectively, without the formation of a wetting layer. The Kelvin probe force microscopy (KPFM) study allowed to get qualitative and quantitative information about the work function of cluster and islands observed for the different metals on the AlN(0001) surface.