Direct observation of band-edge luminescence and alloy luminescence from ultrametastable silicon-germanium alloy layers
Abstract
Ultrametastable silicon-germanium (Si1-xGex) layers with a Ge content x in the range from about 20% to 27% were grown by Si-MBE at temperatures far below 550 °C (325-450 °C). The thicknesses of the layers (up to 500 nm) exceed the equilibrium thickness by a factor of up to 50. We observe in the as-grown samples without any annealing both the excitonic Si1-xGex band-edge luminescence and a broad alloy luminescence of unknown origin. The two peaks have an energy difference of ≊144 meV and shift linearly with the Ge content. The alloy band luminescence disappears when strain relaxation sets on upon annealing at around 600 °C.
- Publication:
-
Applied Physics Letters
- Pub Date:
- April 1992
- DOI:
- 10.1063/1.107199
- Bibcode:
- 1992ApPhL..60.1729S
- Keywords:
-
- Band Structure Of Solids;
- Germanium Alloys;
- Luminescence;
- Molecular Beam Epitaxy;
- Optoelectronic Devices;
- Silicon Alloys;
- Annealing;
- Electron Transitions;
- Metastable State;
- Quantum Wells;
- Vapor Deposition;
- Solid-State Physics