Wang Naiyin, Wong Wei Wen, Yuan Xiaoming, Li Li, Jagadish Chennupati, Tan Hark Hoe
Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia.
Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan, 410083, P. R. China.
Small. 2021 May;17(21):e2100263. doi: 10.1002/smll.202100263. Epub 2021 Apr 15.
There is a strong demand for III-V nanostructures of different geometries and in the form of interconnected networks for quantum science applications. This can be achieved by selective area epitaxy (SAE) but the understanding of crystal growth in these complicated geometries is still insufficient to engineer the desired shape. Here, the shape evolution and crystal structure of InP nanostructures grown by SAE on InP substrates of different orientations are investigated and a unified understanding to explain these observations is established. A strong correlation between growth direction and crystal phase is revealed. Wurtzite (WZ) and zinc-blende (ZB) phases form along <111>A and <111>B directions, respectively, while crystal phase remains the same along other low-index directions. The polarity induced crystal structure difference is explained by thermodynamic difference between the WZ and ZB phase nuclei on different planes. Growth from the openings is essentially determined by pattern confinement and minimization of the total surface energy, regardless of substrate orientations. A novel type-II WZ/ZB nanomembrane homojunction array is obtained by tailoring growth directions through alignment of the openings along certain crystallographic orientations. The understanding in this work lays the foundation for the design and fabrication of advanced III-V semiconductor devices based on complex geometrical nanostructures.
对于用于量子科学应用的不同几何形状且呈互连网络形式的III-V族纳米结构有着强烈需求。这可以通过选择性区域外延（SAE）来实现，但对于这些复杂几何形状中的晶体生长的理解仍不足以设计出所需形状。在此，研究了通过SAE在不同取向的InP衬底上生长的InP纳米结构的形状演变和晶体结构，并建立了一个统一的理解来解释这些观察结果。揭示了生长方向与晶相之间的强相关性。纤锌矿（WZ）相和闪锌矿（ZB）相分别沿<111>A和<111>B方向形成，而沿其他低指数方向晶相保持不变。极性引起的晶体结构差异通过不同平面上WZ相和ZB相核之间的热力学差异来解释。从开口处的生长基本上由图案限制和总表面能的最小化决定，而与衬底取向无关。通过沿特定晶体学取向对齐开口来调整生长方向，获得了一种新型的II型WZ/ZB纳米膜同质结阵列。这项工作中的理解为基于复杂几何纳米结构的先进III-V族半导体器件的设计和制造奠定了基础。
