Andreev reflection in Si-engineered Al/InGaAs hybrid junctions

Andreev-reflection dominated transport is demonstrated in Al/n-In0.38Ga0.62As superconductor-semiconductor junctions grown by molecular beam epitaxy on GaAs(001). High junction transparency was achieved in low-doped devices by exploiting Si interface bilayers to suppress the native Schottky barrier. It is argued that this technique is ideally suited for the fabrication of ballistic transport hybrid microstructures.Comment: 9 REVTEX pages + 3 postscript figures, to be published in APL 73, (28dec98