Magnetic-field-induced retardation of the recombination of nonequilibrium charge carriers in semiconductors

The retardation of the recombination of electrons and holes in semiconductors in an applied uniform magnetic field has been predicted. It has been shown that the recombination time in germanium in the temperature range of $T=(1{-}10)$ K at charge carrier densities of $n_ e=(10^{10}{-}10^{14}$ cm$^{-3}$ in magnetic fields of $B=(3\cdot10^2{-}3\cdot10^4)\,$G can be more than two orders of magnitude larger than that at zero magnetic field. This means that, after creation of nonequilibrium charge carriers by their injection at the $p{-}n$ junction owing to some radiation sources or fast electron irradiation, the semiconductor retains its conductivity for a much longer time at nonzero applied magnetic field. The effect under study can be used, for example, to detect radiation sources.