Wang Jiaming, Wang Mingxing, Xu Fujun, Liu Baiyin, Lang Jing, Zhang Na, Kang Xiangning, Qin Zhixin, Yang Xuelin, Wang Xinqiang, Ge Weikun, Shen Bo
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China.
Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, 100871, Beijing, China.
Light Sci Appl. 2022 Mar 24;11(1):71. doi: 10.1038/s41377-022-00753-4.
Solving the doping asymmetry issue in wide-gap semiconductors is a key difficulty and long-standing challenge for device applications. Here, a desorption-tailoring strategy is proposed to juggle the carrier concentration and transport. Specific to the p-doping issue in Al-rich AlGaN, self-assembled p-AlGaN superlattices with an average Al composition of over 50% are prepared by adopting this approach. The hole concentration as high as 8.1 × 10 cm is thus realized at room temperature, which is attributed to the significant reduction of effective Mg activation energy to 17.5 meV through modulating the activating path, as well as the highlighted Mg surface-incorporation by an intentional interruption for desorption. More importantly, benefiting from the constant ultrathin barrier thickness of only three monolayers via this approach, vertical miniband transport of holes is verified in the p-AlGaN superlattices, greatly satisfying the demand of hole injection in device application. 280 nm deep-ultraviolet light-emitting diodes are then fabricated as a demo with the desorption-tailored Al-rich p-AlGaN superlattices, which exhibit a great improvement of the carrier injection efficiency and light extraction efficiency, thus leading to a 55.7% increase of the light output power. This study provides a solution for p-type doping of Al-rich AlGaN, and also sheds light on solving the doping asymmetry issue in general for wide-gap semiconductors.
解决宽禁带半导体中的掺杂不对称问题是器件应用面临的关键难题和长期挑战。在此，我们提出一种解吸调控策略来调节载流子浓度和输运。针对富铝AlGaN中的p型掺杂问题，采用该方法制备了平均铝组分为50%以上的自组装p型AlGaN超晶格。通过调制激活路径，有效Mg激活能显著降低至17.5 meV，以及通过有意中断解吸突出Mg表面掺入，从而在室温下实现了高达8.1×10¹⁸ cm⁻³的空穴浓度。更重要的是，通过该方法受益于仅三个单分子层的恒定超薄势垒厚度，在p型AlGaN超晶格中验证了空穴的垂直微带输运，极大地满足了器件应用中空穴注入的需求。然后，以解吸调控的富铝p型AlGaN超晶格为示例制作了280 nm深紫外发光二极管，其载流子注入效率和光提取效率有了很大提高，从而使光输出功率提高了55.7%。本研究为富铝AlGaN的p型掺杂提供了解决方案，也为解决宽禁带半导体普遍存在的掺杂不对称问题提供了思路。
