Portal de Periódicos da CAPES

STM characterization of the Si-P heterodimer

2004; American Physical Society; Volume: 69; Issue: 19 Linguagem: Inglês

10.1103/physrevb.69.195303

1550-235X

Neil J. Curson, Steven R. Schofield, M. Y. Simmons, L. Oberbeck, Jeremy L. O’Brien, Robert G. Clark,

Molecular Junctions and Nanostructures

We use scanning tunneling microscopy (STM) and Auger electron spectroscopy to study the behavior of adsorbed phosphine $({\mathrm{PH}}_{3})$ on Si(001), as a function of annealing temperature, paying particular attention to the formation of the Si-P heterodimer. Dosing the Si(001) surface with $\ensuremath{\sim}0.002$ langmuirs of ${\mathrm{PH}}_{3}$ results in the adsorption of ${\mathrm{PH}}_{x}$ $(x=2,3)$ onto the surface and etching of Si to form individual Si ad-dimers. Annealing to $350\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ results in the incorporation of P into the surface layer to form Si-P heterodimers and the formation of short one-dimensional Si dimer chains and monohydrides. In filled state STM images, isolated Si-P heterodimers appear as zigzag features on the surface due to the static dimer buckling induced by the heterodimer. In the presence of a moderate coverage of monohydrides this static buckling is lifted, rending the Si-P heterodimers invisible in filled state images. However, we find that we can image the heterodimer at all H coverages using empty state imaging. The ability to identify single P atoms incorporated into Si(001) will be invaluable in the development of nanoscale electronic devices based on controlled atomic-scale doping of Si.