ABSTRACT
Far IR emission and current-voltage characteristics of p-type strained MQW InxGa1-xAs/GaAs heterostructures in high lateral electric fields are investigated. Highly nonequilibrium phenomena observed are shown to results from the escape of hot holes from the quantum wells into barrier layers. The simple experimental criterion for the population inversion between barrier and quantum well states is put forward. The population inversion is shown to realize in "shallow" (with respect to the optical phonon energy) InxGa1-xAs quantum wells that opens the possibility for the amplification of far infrared radiation and lasing at intravalence-band optical transitions.
