Intersubband transitions within the conduction band in semiconductor quantum wells have been widely explored, which eventually led to their application in quantum well infrared photodetectors and quantum cascade lasers (QCLs). There have been considerably fewer studies of hole intersubband transitions, which are more complicated than their electronic counterparts. They are very interesting, however, because of optical activity for both TM and TE light polarization, offering the possibility of both edge and surface-normal emission or absorption. Earlier studies have mostly focused on bound-continuum transitions in GaAs/AlGaAs and Si/SiGe systems for infrared detection. The interest in hole intersubband transitions has been recently renewed in view of their application for mid- and far-infrared emitters, including QCLs. Considerable progress has been made in the design and realization of p-doped Si/SiGe quantum cascades and luminescence has been obtained in the THz  and mid-infrared  range, although laser action has yet to be demonstrated.
|Title of host publication
|21st IEEE International Semiconductor Laser Conference, ISLC 2008
|Institute of Electrical and Electronics Engineers Inc.
|Number of pages
|Published - 30 Sep 2008
|21st IEEE International Semiconductor Laser Conference - Sorrento, Italy
Duration: 14 Sep 2008 → 18 Sep 2008
Conference number: 21
|Conference Digest - IEEE International Semiconductor Laser Conference
|21st IEEE International Semiconductor Laser Conference
|14/09/08 → 18/09/08