Achieving atomically ordered GaN/AlN quantum heterostructures: The role of surface polarity
Achieving atomically ordered GaN/AlN quantum heterostructures: The role of surface polarity
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DOI：
10.1073/pnas.2303473120
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发表时间：
2023-09-12
影响因子：
11.1
通讯作者：
Mi，Zetian
中科院分区：
文献类型：
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作者：
Wu，Yuanpeng;Zhou，Peng;Mi，Zetian
原子尺度异质结构的界面工程一直是纳米尺度和量子材料科学的中心研究热点。尽管其至关重要，但原子有序异质界面的实现却受到异质结构中界面原子的强扩散特征的严重限制。在这项工作中，我们首先报告了界面扩散对表面极性的强烈依赖性。近乎完美的量子界面可以很容易地在半极性面上合成，而不是在 GaN/AlN 异质结构的传统 c 面上。第一性原理计算证明，半极性面上的化学键构型可以显着抑制阳离子取代过程，从而形成原子级尖锐的界面。此外，GaN/AlN 的表面极性可以通过改变核壳纳米结构的应变弛豫过程来轻松控制。所获得的极其受限、无相互扩散的超薄 GaN 量子阱表现出约 75% 的高内量子效率。深紫外发光二极管采用可扩展且稳健的方法制造，电致发光发射几乎不受量子限制斯塔克效应的影响，这对于超稳定的器件运行具有重要意义。所提出的工作展示了实现III族氮化物以及其他极性材料（例如III族砷化物、钙钛矿等）原子有序量子异质结构的重要途径。
Interface engineering in heterostructures at the atomic scale has been a central research focus of nanoscale and quantum material science. Despite its paramount importance, the achievement of atomically ordered heterointerfaces has been severely limited by the strong diffusive feature of interfacial atoms in heterostructures. In this work, we first report a strong dependence of interfacial diffusion on the surface polarity. Near-perfect quantum interfaces can be readily synthesized on the semipolar plane instead of the conventionalc-plane of GaN/AlN heterostructures. The chemical bonding configurations on the semipolar plane can significantly suppress the cation substitution process as evidenced by first-principles calculations, which leads to an atomically sharp interface. Moreover, the surface polarity of GaN/AlN can be readily controlled by varying the strain relaxation process in core–shell nanostructures. The obtained extremely confined, interdiffusion-free ultrathin GaN quantum wells exhibit a high internal quantum efficiency of ~75%. Deep ultraviolet light-emitting diodes are fabricated utilizing a scalable and robust method and the electroluminescence emission is nearly free of the quantum-confined Stark effect, which is significant for ultrastable device operation. The presented work shows a vital path for achieving atomically ordered quantum heterostructures for III-nitrides as well as other polar materials such as III-arsenides, perovskites, etc.