Interface phonons in asymmetric quantum well structures.

P. Kinsler, R.W. Kelsall, P. Harrison. 

    Institute of Microwaves and Photonics, 
    School of Electronic and Electrical Engineering, 
    University of Leeds, 
    Leeds LS2 9JT,
    United Kingdom.

    Superlattices and Microstructures, 25, 163 (1999).

In semiconductor microstructures with many layers, the phonon
modes change from their bulk form and split into "confined LO
phonons" (LC) and "interface phonons" (IF), the number and
variety of which depends on both the number of layers and the
number of different materials in the structure.  This affects the
electron--phonon scattering rates.  Because of the current
interest in inter-subband THz emitters, we use these LC and IF
modes to evaluate the inter-subband electron--phonon scattering
rate in THz emitter prototypes that are based on four-subband
stepped quantum wells.  These scattering rates in turn affect the
population inversion predicted for these devices, so we compare
the predicted population inversions for the most promising
prototypes against those obtained using bulk phonon scattering
rates.




Email: Dr.Paul.Kinsler@physics.org