Extremely high electron mobility in isotopically-enriched Si two-dimensional electron gases grown by chemical vapor deposition

Both depletion-mode and enhancement-mode two-dimensional electron gases (2DEGs) in isotopically enriched Si with extremely high mobility (522 000 cm/V s) are presented. The samples were grown by chemical vapor deposition using enriched silane. The fraction of the spin-carrying isotope Si was reduced to the level of 800 ppm by Si enrichment, with the electron spin dephasing time expected to be as long as 2 ls. 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 2DEGs. VC 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4824729]