Extremely High Electron Mobility In Isotopically-Enriched Si-28 Two-Dimensional Electron Gases Grown By Chemical Vapor Deposition

Both depletion-mode and enhancement-mode two-dimensional electron gases (2DEGs) in isotopically enriched Si-28 with extremely high mobility (522 000 cm(2)/V s) are presented. The samples were grown by chemical vapor deposition using enriched silane. The fraction of the spin-carrying isotope Si-29 was reduced to the level of 800 ppm by 28 Si enrichment, with the electron spin dephasing time expected to be as long as 2 mu s. Remote impurity charges from ionized dopants and the Si/Al2O3 interface were suggested to be the dominant source for electron scattering in the enriched Si-28 2DEGs. (C) 2013 AIP Publishing LLC.