Neutral impurity scattering in mercury-doped germanium

A hole mobility analysis is described for weakly compensated mercury-doped germanium over a temperature range ($10<T<100$ K) for which neutral Hg acceptors were predominant and made a detectable contribution to hole scattering. It was deduced that μNNN=4.4×10²⁰ cm^-1{V}^{{-}1}s^-1 from 10 to {~} 35 K; a scattering efficiency 40% of that to be expected for a shallow monovalent acceptor. The scattering efficiency appeared to halve between 35 and 50 K, and to continue at a rate consistent with μNNN=8.8×10²⁰ cm^-1{V}^{{-}1}s^-1 from 50 K upwards. Thus even in the upper part of the temperature range, Hg⁰ acceptors were twice as efficient in scattering as might have been supposed from the mercury center's first ionization energy. It is noted that the ratio of hole wavelength to interacceptor spacing was propitious for a contribution to scattering by acceptor pairs. That complication would not be easy to avoid experimentally.