Localised and resonant states of shallow acceptors in Ge/Ge1−xSix multiple-quantum well heterostructures

A new theoretical approach allowing to calculate both the localised and the continuum states of charge carriers in QW heterostructures in the presence of the Coulomb potential has been developed. The method allows to satisfactorily describe the observed photoconductivity spectra of Ge/GeSi heterostructures. The optical transitions from the acceptor ground states to the resonant states have been revealed in the measured far IR photoconductivity spectra.