Few-electron quantum-device impact of oxygen reduction

Establish whether reducing the oxygen background near the active silicon quantum well through insertion of an electrically passive buried silicon layer translates into improved few-electron quantum-device operation.

Background

The paper demonstrates that inserting a thin, electrically passive silicon layer into the lower SiGe barrier reduces the oxygen concentration near the active silicon quantum well and increases the absolute electron mobility in RP-CVD-grown Si/SiGe heterostructures. However, the reported measurements are based on Hall-bar field-effect transistors and transport metrics such as mobility, percolation density, and density-dependent mobility scaling, rather than direct few-electron quantum-device experiments.

The unresolved issue is whether the materials improvement produced by oxygen trapping yields a practical benefit in quantum-device operation, such as improved control or stability in the few-electron regime. The paper leaves this question for direct experimental investigation in quantum-dot or related few-electron devices.