Double injection in a large cylindrical p+‐π‐n+ germanium structure

摘要

Observation of radial double‐injection semiconductor regime current in a forward biased hollow‐core coaxial p+‐π‐n+ germanium device is reported. The cylindrical structure is an annulus with concentric p+ and n+ contacts at the inner and outer radii, respectively. Measurements of the current‐voltage characteristic show linear behavior at low current and an I ∝ V2 relationship at higher injection levels. The magnitude of the double‐injection current is greater than predicted from simple theory, which is attributed to diffusion effects at the carrier injecting boundaries. A correction for these effects is discussed in terms of effective radii approximations which can be conveniently incorporated into the first‐order theory.