Conduction band discontinuity and electron confinement at the SixGe1−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 Si0.1Ge0.9/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.