High electron mobility in modulation-doped Si/SiGe quantum well structures

Modulation-doped multiple quantum well structures based on Si/SiGe have been grown by molecular beam epitaxy. Low-temperature electron mobilities up to 17 000 cm²/V s have been achieved in narrow Si quantum wells. The electronic properties of the strain symmetrized Si/SiGe multilayer structures were studied by magnetotransport and cyclotron resonance experiments. The results are consistent with subband calculations which take the strain-induced splitting of the conduction band and the lowering of two valleys into account.