Quasi-two-dimensional electron–hole liquid and biexcitons in SiGe layers of Si/SiGe/Si heterostructures



The electron–hole liquid (EHL) in quantum-confinement SiGe layers of Si/Si1-xGex /Si heterostructures is discovered and its properties are studied by photoluminescence spectroscopy in the near-infrared and visible spectral ranges. It is established that the EHL is composed by quasi-two-dimensional holes in the quantum well formed by the SiGe layer and quasi-three-dimensional electrons, which occupy a wider region of space centered on this layer. Conditions on the band parameters of a type-II heterostructure under which the formation of the EHL and biexcitons in such a structure is possible are determined. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)