Photoluminescence investigation of phononless radiative recombination and thermal-stability of germanium hut clusters on silicon(001)

Abstract

Intense photoluminescence (PL) originating from single layers of germanium hut clusters grown on silicon (001) is investigated using PL spectroscopy. We propose that the luminescence originates from phononless recombination within a spatially indirect, type-II neighboring confinement structure. Enhanced no-phonon (NP) luminescence is attributed to exciton localization at the Ge/Si interfaces. The PL intensity is sensitive to the growth temperature during interface formation, as well as to post-growth thermal annealing, illustrating the influence of atomic-level Si–Ge intermixing on exciton localization and NP enhancement.