Inverted modulation-doped n-type Si/Si0.77Ge0.23 heterostructures

Inverted n-type modulated-doped Si/Si0.77Ge0.23 heterostructures have been prepared using ex-situ ion implantation of a virtual substrate for the dopi ng followed by cleaning and the regrowth of the silicon quantum well in the growth system. At 1.7K sample mobilities of 1.5-7.3x10(4)cm(2)/Vs and carr ier densities of 4.25-14.51x10(11)cm(-2) were obtained. The sample mobility was observed to decrease with increasing ion dose land carrier density). C lear Shubnikov-de Haas oscillations and quantum Hall effect plateaux were v isible, demonstrating the quality of the technique.