Formation of low-dimensional GaN on trenched Si(5512), probed by STM and XPS

Abstract

We report the formation of self-assembled nanostructures of GaN, with controlled size and shape on the trenched planar Si (5 512) surface. Adsorbing low coverages of Ga on Si (55 12) forms 1D arrays of Ga adatoms. The Ga adsorbed Si surface is annealed to 300 degrees C, which results in the formation of Ga 2D nanoparticles (NPs). These Ga NPs were exposed to various fluence of energetic 2 keV N-2(+) ions followed by annealing which yields GaN nanostructures self-assembled along the <(1) over bar 10 > direction. These studies were performed in ultrahigh vacuum using in situ scanning tunneling microscopy and ex situ x-ray photoelectron spectroscopy, to observe the structural and chemical evolution of the interface.