Narrow photoluminescence peak from Ge(Si) islands embedded between tensile‐strained Si layers

Abstract

AbstractThe influence of thickness of the strained Si layers, measurement temperature and optical pumping power on width of the photoluminescence line from Ge(Si) self‐assembled nanoislands grown on relaxed SiGe/Si(001) buffer layers and embedded between tensile‐stained Si layers was studied. This line appears due to the II‐type optical transition between the holes localized in islands and the electrons confined in tensile‐strained Si layers under and above the islands. The possibility of tuning the photoluminescence line width by changing the strained Si layer thicknesses under and above the islands is showed. The decrease of the photoluminescence line width from Ge(Si) islands down to values comparable with width of the PL line from InAs/GaAs quantum dots was achieved due to the quantum confinement of electrons in thin strained Si layers and taking into account of the higher diffusion‐induced smearing of strained Si layer above the islands. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)