Spatially direct and indirect transitions of self-assembled GeSi/Si quantum dots studied by photoluminescence excitation spectroscopy

Abstract

Well-resolved photoluminescence excitation (PLE) spectra are reported for self-assembled GeSi dots grown on Si(001) by molecular beam epitaxy. The observation of two excitation resonance peaks is attributed to two different excitation/de-excitation routes of interband optical transitions connected to the spatially direct and indirect recombination processes. It is concluded that two dot populations are addressed by each monitored luminescence energy for the PLE acquisition. © 2010 American Institute of Physics.