Ma Shuo, Pan Wenwu, Sun Xiao, Zhang Zekai, Gu Renjie, Faraone Lorenzo, Lei Wen
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Perth, WA 6009, Australia.
John de Laeter Center, Curtin University, Bentley, WA 6102, Australia.
Molecules. 2024 Aug 21;29(16):3947. doi: 10.3390/molecules29163947.
In this paper, we present a study on the direct growth of Hg0.7Cd0.3Te thin films on layered transparent van der Waals mica (001) substrates through weak interface interaction through molecular beam epitaxy. The preferred orientation for growing Hg0.7Cd0.3Te on mica (001) substrates is found to be the (111) orientation due to a better lattice match between the Hg0.7Cd0.3Te layer and the underlying mica substrate. The influence of growth parameters (mainly temperature and Hg flux) on the material quality of epitaxial Hg0.7Cd0.3Te thin films is studied, and the optimal growth temperature and Hg flux are found to be approximately 190 °C and 4.5 × 10-4 Torr as evidenced by higher crystalline quality and better surface morphology. Hg0.7Cd0.3Te thin films (3.5 µm thick) grown under these optimal growth conditions present a full width at half maximum of 345.6 arc sec for the X-ray diffraction rocking curve and a root-mean-square surface roughness of 6 nm. However, a significant number of microtwin defects are observed using cross-sectional transmission electron microscopy, which leads to a relatively high etch pit density (mid-107 cm-2) in the Hg0.7Cd0.3Te thin films. These findings not only facilitate the growth of HgCdTe on mica substrates for fabricating curved IR sensors but also contribute to a better understanding of growth of traditional zinc-blende semiconductors on layered substrates.
在本文中，我们展示了一项关于通过分子束外延，利用弱界面相互作用在层状透明范德华云母（001）衬底上直接生长Hg0.7Cd0.3Te薄膜的研究。由于Hg0.7Cd0.3Te层与下层云母衬底之间具有更好的晶格匹配，发现在云母（001）衬底上生长Hg0.7Cd0.3Te的择优取向为（111）取向。研究了生长参数（主要是温度和Hg通量）对外延Hg0.7Cd0.3Te薄膜材料质量的影响，发现最佳生长温度和Hg通量分别约为190°C和4.5×10-4托，这由更高的晶体质量和更好的表面形貌所证明。在这些最佳生长条件下生长的Hg0.7Cd0.3Te薄膜（3.5μm厚）的X射线衍射摇摆曲线半高宽为345.6弧秒，表面粗糙度均方根为6nm。然而，使用横截面透射电子显微镜观察到大量微孪晶缺陷，这导致Hg0.7Cd0.3Te薄膜中的蚀刻坑密度相对较高（107 cm-2 左右）。这些发现不仅有助于在云母衬底上生长HgCdTe以制造曲面红外传感器，还有助于更好地理解传统闪锌矿半导体在层状衬底上的生长。
