The effect of single-phonon and plasmon recombination on the lifetime in n-Hg1−xCdxTe with magnetically tuned bandgap

Abstract

Theoretical investigations have predicted a great enhancement of electron-hole recombinations by adjusting the bandgap of narrow-gap semiconductors to the energy of elementary excitation in solids such as phonons or plasmons. Such an enhancement of the recombination rate of excess carriers is very important in constructing far-I.R. devices and might be used to generate high densities of LO-phonons and plasmons. We report experimental evidence of the influence of these recombination channels on the photoconductivity and the excess carrier lifetime in semimetallic n-Hg1−xCdxTe alloys, whose induced bandgap is magnetically tuned through the relevant energies of the elementary excitations. Both from a comparison of theoretically estimated lifetimes with Auger lifetimes and from experimental observations the new recombination channels prove to be very efficient and dominate the behaviour near their resonance with the band-gap.