Realization of wide electron slabs by polarization bulk doping in graded III–V nitride semiconductor alloys

We present the concept and experimental realization of polarization-induced bulk electron doping in III–V nitride semiconductors. By exploiting the large polarization charges in the III–V nitrides, we are able to create wide slabs of high-density mobile electrons without introducing shallow donors. Transport measurements reveal the superior properties of the polarization-doped electron distributions than comparable shallow donor-doped structures, especially at low temperatures due to the removal of ionized impurity scattering. Such polarization-induced three-dimensional electron slabs can be utilized in a variety of device structures owing to their high conductivity and continuously changing energy gap.