Polarization-Induced p-Type Doping in Graded InGaN: From Predictive Modeling to Device Testing

Distributed polarization-induced p-type doping (DPD) in III-nitride heterostructures offers an alternative to conventional Mg acceptor doping, which is limited by low activation efficiency and parasitic optical absorption in optoelectronic devices such as lasers. Here, mobile hole populations are engineered in compositionally graded InGaN layers and superlattices via polarization-induced charge accumulation, with Hall measurements yielding sheet hole densities on the order of 1 × 1013 cm−2. These values are in quantitative agreement with self-consistent one-dimensional Poisson−Schrödinger simulations, demonstrating the predictive capability of polarization-doped structure design. To assess device functionality, these p-type DPD regions were incorporated into simple GaN-based light-emitting diodes. The resulting devices exhibit current−voltage characteristics and optical output comparable to reference LEDs employing p-GaN, despite the absence of bulk Mg doping. These results demonstrate the feasibility of polarization-induced p-type doping for hole injection in vertical III-nitride devices and provide a foundation for future investigations of visible-wavelength laser architectures, where reducing Mg-related optical loss is of particular interest.