Plasmon‐assisted recombination in narrow‐gap semiconductors in a magnetic field

Abstract

This paper presents calculations of the effect of large magnetic fields on the plasmon-assisted recombination process in narrow-gap semiconductors. Minority carriers, in materials such as n-(Pb,Sn)Te or n-(Hg,Cd)Te, are believed to recombine via plasma wave emission when EG ≤ ħwp; lifetimes in the 10−12 −10−13 sec range are anticipated This large recombination rate precludes stimulated plasma wave emission. Magnetic fields change the plasmon recombination process in two ways. Landau level quantization enhances the electron state density at the band edge, increasing the gain of k = 0 plasma modes. The field also modifies the plasmon dispersion relation; this effect can be exploited to inhibit recombination via plasma modes propagating across the field, and to increase the recombination time. The two effects combine to yield a threshold pumping level for stimulated plasma wave emission in the 10–100 kW/cm2 range.