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18 February 2011 THz lasing concepts based upon InAs/GaSb broken-gap heterostructures
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Proceedings Volume 7938, Terahertz Technology and Applications IV; 79380C (2011)
Event: SPIE OPTO, 2011, San Francisco, California, United States
This paper will illustrate the potential of InAs/GaSb broken-gap structures for providing a solution to the well-known and long-standing terahertz (THz) frequency gap in source technology. In a double-barrier GaSb/InAs/GaSb heterostructure, the ultrafast heavy-hole interband tunneling can be utilized to achieve electron depopulation of a quasibound, heavy-hole level located in the valence-band of the right GaSb barrier region. A population inversion is then created using electron injection into the conduction-band resonant state of the double-barrier structure. Degrading nonradiative processes such as acoustic phonon, optical phonon and Auger recombination are suppressed in this spatially separated two-level energy system. Hence, heavy-hole interband tunneling prevails over nonradative transition rates and establishes a population inversion at relatively high operating temperatures. Detailed simulations predict a significant optical (total) gain of ~0.001 which is comparable with GaAs/AlGaAs quantum well laser in spite of the small overlap of conduction band and heavy-hole wavefunctions. The TE emission allows for implementation of vertical surface emission in large area, for single or arrayed devices. Also, lateral quantum confinement of arrayed systems can be used to reduce the conduction band current density (and undesired thermal heating) and increase the quantum efficiency.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Dwight Woolard and Weidong Zhang "THz lasing concepts based upon InAs/GaSb broken-gap heterostructures", Proc. SPIE 7938, Terahertz Technology and Applications IV, 79380C (18 February 2011);

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