Carrier Capture Probabilities in Nickel Doped Germanium

Nickel has been diffused into germanium in order to study the carrier capture probabilities of the two nickel acceptor levels. Measurements of minority carrier lifetime as a function of temperature show that the electron capture probability of low-resistivity $p$-type samples is temperature-independent. The electron capture probability of high-resistivity $p$-type samples increases exponentially with increasing temperature, as does the hole capture probability of high-resistivity $n$-type samples. Possible interpretations of the results are discussed.