Composition and strain of the pseudomorphic α-phase intermediate layer at the Ga2O3/Al2O3 interface

IF 5.3 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

APL Materials Pub Date : 2024-09-05 DOI:10.1063/5.0226857

M. Schowalter, A. Karg, M. Alonso-Orts, J. A. Bich, S. Raghuvansy, M. S. Williams, F. F. Krause, T. Grieb, C. Mahr, T. Mehrtens, P. Vogt, A. Rosenauer, M. Eickhoff

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Abstract

We investigate the composition of α-phase intermediate layers at epitaxial Ga2O3/Al2O3 interfaces using high angle annular dark field scanning transmission electron microscopy. Their presence is considered a general phenomenon as they are observed independent of the growth technique [Schewski et al., Appl. Phys. Exp. 8, 011101]. Samples were grown by plasma assisted molecular beam epitaxy using different growth conditions. Almost independent of these, the quantitative evaluation of the measured intensities gave Ga concentrations of ∼25%. We show that the previously published model, based on a pure α-Ga2O3 interlayer, fails if it is adapted to the measured composition. Density functional theory (DFT) computations were used to overcome the approximations made in this model and suggest that a stabilization of the layer is possible due to the low Ga concentration (≤35%) at which the α-phase is the most stable. Our surface model computations suggest an exchange of Ga atoms at the surface with Al atoms from the underlying substrate as a possible formation mechanism.

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Ga2O3/Al2O3 界面伪α相中间层的成分和应变

我们利用高角度环形暗场扫描透射电子显微镜研究了外延 Ga2O3/Al2O3 界面上 α 相中间层的组成。它们的存在被认为是一种普遍现象，因为观察到它们与生长技术无关[Schewski 等人，《应用物理实验》8，011101]。样品是通过等离子体辅助分子束外延技术在不同的生长条件下生长出来的。几乎与这些条件无关，对测量强度的定量评估得出的镓浓度为 25%。我们的研究表明，如果将以前发表的基于纯 α-Ga2O3 夹层的模型与测量到的成分相适应，该模型就会失效。密度泛函理论（DFT）计算克服了这一模型中的近似值，并表明由于镓的浓度较低（≤35%），α-相最稳定，因此层的稳定是可能的。我们的表面模型计算表明，表面的镓原子与底层基底的铝原子交换是一种可能的形成机制。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

APL Materials NANOSCIENCE & NANOTECHNOLOGYMATERIALS SCIE-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

9.60

自引率

3.30%

发文量

199

审稿时长

2 months

期刊介绍： APL Materials features original, experimental research on significant topical issues within the field of materials science. In order to highlight research at the forefront of materials science, emphasis is given to the quality and timeliness of the work. The journal considers theory or calculation when the work is particularly timely and relevant to applications. In addition to regular articles, the journal also publishes Special Topics, which report on cutting-edge areas in materials science, such as Perovskite Solar Cells, 2D Materials, and Beyond Lithium Ion Batteries.