Solving the Asymmetric Doping for Wide-Gap Semiconductors by Host Functionalization: Quantum Engineering Strategy

Asymmetric doping of wide-gap semiconductors has long been a major challenge, hindering their wider applications. Despite numerous attempts to address this issue through engineering doping levels, the results were still inconclusive. In this work, we propose a quantum engineering strategy based on the state-of-the-art spin-polarized HSE06 hybrid functional method. The local band offset between the host and quantum structures can considerably compensate for the large carrier activation energy (E_a). We chose the system of the AlN host embedded by GaN quantum dots as an example to validate the feasibility of this strategy. The E_a of Si (n-type) and Be (p-type) dopants can be reduced from 222 and 404 meV to negative values and 2 meV, respectively. Therefore, electron and hole density can be increased to more than 10¹⁹ and 10²⁰ cm^-3, respectively. We also tested potential dopants (C and Ge for the n-type, Mg and Ca for the p-type), and the technique is equally effective. This mechanism can also be used to understand the experimental observations of the superlattice doping strategy. Overall, our study demonstrates that the quantum engineering strategy provides a potential solution to overcome the asymmetric doping problem for universal wide-gap semiconductors and supports a feasible pathway for more efficient devices in the future.