Photoluminescence of Ge/Si Nanostructures with Ge Quantum Dots

Abstract

Photoluminescence (PL) of Ge/Si nanostructures with Ge quantum dots (QDs) at 5, 78 and 300 K was studied. The nanostructures were grown by molecular beam epitaxy on single-crystal silicon substrates under 2 keV Ge⁺ ion irradiation and without irradiation. An effect of increasing the intensity of a broad PL band  in the energy range of ~0.8 eV was found when the nanostructures were irradiated with Ge⁺ ions. A comparative analysis of the PL spectra recorded from the side of the silicon substrate and from the side of the formation of Ge/Si nanostructures was performed. It was found that during the growth of multilayer Ge/Si nanostructures with Ge QDs at temperatures of 500—600 °C thermal defects of the structure are formed in silicon, causing the appearance of an electron-vibrational bands with zero-phonon lines P ~ 0.767 eV, C ~ 0.789 eV, and H ~ 0.926 eV.