Recombination of Electrons and Donors inn-Type Germanium. B

A study is made of two possible recombination mechanisms for electrons and ionized donors in Ge. The first consists of two successive transitions ending in the ground state of the donor and having an excited state as an intermediate level. Two phonons are emitted. The second mechanism is that of impact recombination. It is shown that the first mechanism is dominant at liquid helium temperatures for electron concentrations less than 4×{}10^-15 cm^-3. At higher concentrations impact recombination dominates the rate of approach to equilibrium.