Quantum structure for efficient p-doping of AlGaN with Al content over 70%

The low p-doping efficiency of AlGaN due to its high activation energy limits the advancement of deep ultraviolet optoelectronics. The quantum engineering method has provided a new insight to address the challenge of acceptor activation in Al-rich AlGaN. As its unique valence band offset, the distribution of acceptor and band edge states in the barrier and well determines the acceptor activation efficiency. Here, we proposed a model for reducing the acceptor activation energy in quantum-structured p-AlGaN and provided experimental validation. By tuning the reactor pressure, we prepared periodic quantum-structured p-AlGaN with different cycles successfully. Compared to long-period quantum structures, short-period quantum structures introduce more band offsets, enhancing the wavefunction overlap between the acceptor states and the band edge states, thereby significantly promoting acceptor activation. Ultimately, we achieved an ultrathin quantum-structure p-AlGaN with an average Al content of ∼77% and a periodic thickness of 2.7 nm, reaching a record-low resistivity value of about 5.4 Ω·cm. Additionally, it is demonstrated that short-period quantum structures can facilitate hole injection in deep ultraviolet light-emitting diodes, effectively improving their external quantum efficiency. This study offers an effective p-doping strategy for Al-rich AlGaN and paves the way for applications of deep ultraviolet optoelectronics.