近日，日本名古屋大学的Hiroshi Amano&Jia Wang及其研究团队取得一项新进展。经过不懈努力，他们观察到二维镁插层氮化镓超晶格。相关研究成果已于2024年6月5日在国际权威学术期刊《自然》上发表。

该研究团队在常压下观察到，通过在氮化镓（GaN）上退火金属镁（Mg）薄膜，能自发形成Mg嵌入GaN的超晶格，这标志着二维金属嵌入块状半导体的首个案例。在此超晶格中，每个Mg单层复杂地插入数个六方GaN单层之间。这种结构呈现出间质插层特征，在垂直于间隙层的方向上产生了显著的单轴压缩应变，使得Mg嵌入GaN超晶格中的GaN层展现出超过10%的特殊弹性应变（相当于超过20GPa的应力），是薄膜材料中最高的记录之一。

应变改变了电子能带结构，极大地增强了空穴沿压缩方向的输运。此外，镁片诱导了GaN极性的独特周期性转变，进而产生了极化场诱导的净电荷。这些特性为半导体掺杂和电导率增强，以及纳米材料和金属半导体超晶格的弹性应变工程提供了新的见解。

据悉，自从p型氮化镓(GaN)通过掺杂取代镁(Mg)原子得到证实以来，蓝色发光二极管等快速而全面的发展，极大地重塑了人们的现代生活，并为一个更加碳中性的社会做出了贡献。然而，氮化镓和镁之间相互作用的细节在很大程度上仍然未知。

附：英文原文

Title: Observation of 2D-magnesium-intercalated gallium nitride superlattices

Author: Wang, Jia, Cai, Wentao, Lu, Weifang, Lu, Shun, Kano, Emi, Agulto, Verdad C., Sarkar, Biplab, Watanabe, Hirotaka, Ikarashi, Nobuyuki, Iwamoto, Toshiyuki, Nakajima, Makoto, Honda, Yoshio, Amano, Hiroshi

Issue&Volume: 2024-06-05

Abstract: Since the demonstration of p-type gallium nitride (GaN) through doping with substitutional magnesium (Mg) atoms, rapid and comprehensive developments, such as blue light-emitting diodes, have considerably shaped our modern lives and contributed to a more carbon-neutral society. However, the details of the interplay between GaN and Mg have remained largely unknown. Here we observe that Mg-intercalated GaN superlattices can form spontaneously by annealing a metallic Mg film on GaN at atmospheric pressure. To our knowledge, this marks the first instance of a two-dimensional metal intercalated into a bulk semiconductor, with each Mg monolayer being intricately inserted between several monolayers of hexagonal GaN. Characterized as an interstitial intercalation, this process induces substantial uniaxial compressive strain perpendicular to the interstitial layers. Consequently, the GaN layers in the Mg-intercalated GaN superlattices exhibit an exceptional elastic strain exceeding 10% (equivalent to a stress of more than 20GPa), among the highest recorded for thin-film materials. The strain alters the electronic band structure and greatly enhances hole transport along the compression direction. Furthermore, the Mg sheets induce a unique periodic transition in GaN polarity, generating polarization-field-induced net charges. These characteristics offer fresh insights into semiconductor doping and conductivity enhancement, as well as into elastic strain engineering of nanomaterials and metal–semiconductor superlattices.

DOI: 10.1038/s41586-024-07513-x

Source: https://www.nature.com/articles/s41586-024-07513-x