Solving the Asymmetric\nDoping for Wide-Gap Semiconductors\nby Host Functionalization: Quantum Engineering Strategy

Asymmetric doping of wide-gap semiconductors has long\nbeen a major\nchallenge, hindering their wider applications. Despite numerous attempts\nto address this issue through engineering doping levels, the results\nwere still inconclusive. In this work, we propose a quantum engineering\nstrategy based on the state-of-the-art spin-polarized HSE06 hybrid\nfunctional method. The local band offset between the host and quantum\nstructures can considerably compensate for the large carrier activation\nenergy (<i>E</i><sub>a</sub>). We chose the system of the\nAlN host embedded by GaN quantum dots as an example to validate the\nfeasibility of this strategy. The <i>E</i><sub>a</sub> of\nSi (n-type) and Be (p-type) dopants can be reduced from 222 and 404\nmeV to negative values and 2 meV, respectively. Therefore, electron\nand hole density can be increased to more than 10<sup>19</sup> and\n10<sup>20</sup> cm<sup>–3</sup>, respectively. We also tested\npotential dopants (C and Ge for the n-type, Mg and Ca for the p-type),\nand the technique is equally effective. This mechanism can also be\nused to understand the experimental observations of the superlattice\ndoping strategy. Overall, our study demonstrates that the quantum\nengineering strategy provides a potential solution to overcome the\nasymmetric doping problem for universal wide-gap semiconductors and\nsupports a feasible pathway for more efficient devices in the future.