Observation of P donors on the Si(111) surface by scanning tunneling microscopy

Abstract

\n \nWe report on the individual observation of substitutional P donors on\nthe reconstructed Si (111) $2\\times1$ surface by means of scanning\ntunneling microscopy and tunneling spectroscopy. Depending on the\nscanning voltage, the dopants give rise to different features\nsuperimposed on the background lattice. This is explained by the\ninfluence of the charged P atom on the electronic surface-states\nresulting in a local band shift. The spatial arrangement of the\ndonors obeys a statistical distribution, excluding significant\nclustering even at a P concentration of $6 \\times 10^{19}$ cm-3\nwhich is far above the metal-insulator transition.\n\n