The quantum cascade laser provides one possible method of realizing high efficiency light emission from indirect band gap materials such as silicon. Strain-symmetrized Si/SiGe samples designed to investigate the intersubband properties of quantum wells are examined. Electroluminescence data from Si/SiGe quantum-cascade staircases demonstrating edge emission from heavy-hole to heavy-hole transitions and light-hole to heavy-hole transitions are presented. In surface-normal emission only light-hole to heavy-hole electroluminescence is observed at 2.9 THz (103 μm wavelength) as predicted by theory. Modulation-doped SiGe quantum well samples are also investigated to determine the underlying physics in the system. Results of picosecond time resolved studies of the dynamics of the intersubband transitions using a free electron laser are presented which show approximately constant relaxation times of 10 ps below 100 K.
|Number of pages||9|
|Journal||Physica E: Low-Dimensional Systems and Nanostructures|
|Early online date||5 Oct 2002|
|Publication status||Published - 1 Jan 2003|
|Event||12th International Winterschool on New Developments in Solids State Physics: "Low- Dimensional Systems: From 2D to Molecules" - Mauterndorf, Austria|
Duration: 25 Feb 2002 → 1 Mar 2002