Conduction band discontinuity and electron confinement at the Si[subscript x]Ge[subscript 1−x]/Ge interface

Germanium rich heterostructures can constitute a valid alternative to Silicon for the confinement of single electron spins. The conduction band discontinuity in SiGe/Ge heterostructures grown on pure germanium substrate is predicted to allow the confinement of electrons in the germanium, and the conduction band profile of germanium rich heterostructures allow the implementation of g-factor modulation devices not possible in Silicon. We here prove that electrons can indeed be trapped at the Si[subscript 0.1]Ge[subscript 0.9]/Ge interface and we measure the height of the energy barrier to 0.55±0.05 eV by measuring the tunneling time of electrons as a function of the electric field.