Department of Chemistry, University of Florence, Via della Lastruccia 3-13, 50019, Sesto, Fiorentino (FI), Italy.
INSTM, Research Unit of Florence, Via della Lastruccia 3-13, 50019, Sesto, Fiorentino (FI), Italy.
Sci Rep. 2017 May 9;7(1):1615. doi: 10.1038/s41598-017-01717-0.
Electrochemical Atomic Layer Deposition (E-ALD) technique has demonstrated to be a suitable process for growing compound semiconductors, by alternating the under-potential deposition (UPD) of the metallic element with the UPD of the non-metallic element. The cycle can be repeated several times to build up films with sub-micrometric thickness. We show that it is possible to grow, by E-ALD, CuS ultra-thin films on Ag(111) with high structural quality. They show a well ordered layered crystal structure made on alternating pseudohexagonal layers in lower coordination. As reported in literature for minerals in the Cu-S compositional field, these are based on CuS triangular groups, with layers occupied by highly mobile Cu ions. This structural model is closely related to the one of the low chalcocite. The domain size of such films is more than 1000 Å in lateral size and extends with a high crystallinity in the vertical growth direction up to more than 10 nm. E-ALD process results in the growth of highly ordered and almost unstrained ultra-thin films. This growth can lead to the design of semiconductors with optimal transport proprieties by an appropriate doping of the intra metallic layer. The present study enables E-ALD as an efficient synthetic route for the growth of semiconducting heterostructures with tailored properties.
电化学原子层沉积（E-ALD）技术已被证明是一种适用于生长化合物半导体的方法，通过交替进行金属元素的欠电位沉积（UPD）和非金属元素的 UPD。该循环可以重复多次，以构建具有亚微米厚度的薄膜。我们证明，通过 E-ALD 可以在 Ag(111)上生长具有高结构质量的 CuS 超薄薄膜。它们显示出由交替的低配位拟六方层组成的有序层状晶体结构。正如文献中报道的在 Cu-S 组成范围内的矿物一样，这些结构基于 CuS 三角形基团，其中层由高度可移动的 Cu 离子占据。这种结构模型与低辉铜矿的结构模型密切相关。这种薄膜的畴尺寸在横向尺寸上超过 1000 Å，并在垂直生长方向上以高结晶度延伸超过 10nm。E-ALD 工艺导致高度有序且几乎无应变的超薄薄膜的生长。通过在金属层内进行适当的掺杂，可以实现具有最佳传输性能的半导体的设计。本研究使 E-ALD 成为生长具有定制性能的半导体异质结构的有效合成途径。
