The intersubband relaxation of holes in p-type modulation-doped Si1-xGex/Si multiple quantum wells is studied both experimentally and theoretically. Pump-probe experiments with 150-fs midinfrared pulses yield a lifetime of holes in the second heavy-hole subband of only 250 fs for 4.4-nm wide wells with x = 0.5. This short lifetime is caused by interaction with phonons via the optical deformation potential. Calculations of hole-phonon scattering agree very well with the experimental results. The calculations show that longer heavy-hole lifetimes are possible by increasing the Ge content and the well widths.
- Intersubband relaxation
- Optical deformation potential
- SiGe quantum wells
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering