Vazquez-Arce Jorge Luis, Amoroso Alessio, Perez Nicolas, Charvot Jaroslav, Naglav-Hansen Dominik, Zhao Panpan, Yang Jun, Lehmann Sebastian, Wrzesińska-Lashkova Angelika, Pieck Fabian, Tonner-Zech Ralf, Bureš Filip, Acquesta Annalisa, Vaynzof Yana, Devi Anjana, Nielsch Kornelius, Bahrami Amin
Leibniz-Institute for Solid State and Materials Research Dresden, Helmholtzstraße 20, 01069, Dresden, Germany.
Department of Chemical Engineering, Materials and Industrial Production, University of Napoli Federico II, Piazzale Tecchio 80, 80125, Napoli, Italy.
Angew Chem Int Ed Engl. 2025 Apr 7;64(15):e202422578. doi: 10.1002/anie.202422578. Epub 2025 Feb 14.
This study presents the first successful demonstration of growing elemental bismuth (Bi) thin films via thermal atomic layer deposition (ALD) using Bi(NMe) as the precursor and Sb(SiMe) as the co-reactant. The films were deposited at a relatively low temperature of 100 °C, with a growth per cycle (GPC) of 0.31-0.34 Å/cycle. Island formation marked the initial growth stages, with surface coverage reaching around 80 % after 1000 cycles and full coverage between 2000 and 2500 cycles. Morphological analysis revealed that the Bi grains expanded and became more defined as the number of ALD cycles increased. This coalescence is further supported by X-ray diffraction (XRD) patterns, which show a preferential shift in growth orientation from the (012) plane to the (003) plane as the film thickness increases. X-ray photoemission spectroscopy (XPS) confirmed the presence of metallic Bi with minimal surface oxidation. Temperature-dependent sheet resistance measurements highlight the semimetallic nature of Bi, with a room temperature resistivity of ≈200 μΩcm for the 2500 cycles Bi. Temperature-dependent sheet resistance was also associated with a transition in carrier-type dominance from holes at higher temperatures to electrones at lower temperatures.
本研究首次成功展示了通过热原子层沉积（ALD）生长元素铋（Bi）薄膜，使用Bi(NMe)作为前驱体，Sb(SiMe)作为共反应物。薄膜在100 °C的相对低温下沉积，每个循环的生长速率（GPC）为0.31 - 0.34 Å/循环。岛状结构标志着初始生长阶段，1000个循环后表面覆盖率达到约80 %，2000至2500个循环之间实现完全覆盖。形态分析表明，随着ALD循环次数增加，Bi晶粒扩大并变得更加清晰。X射线衍射（XRD）图谱进一步支持了这种聚结现象，随着薄膜厚度增加，生长取向从（012）面优先向（003）面转变。X射线光电子能谱（XPS）证实存在金属Bi，表面氧化极少。与温度相关的薄层电阻测量突出了Bi的半金属性质，2500个循环的Bi在室温下的电阻率约为200 μΩcm。与温度相关的薄层电阻还与载流子类型优势从较高温度下的空穴向较低温度下的电子的转变有关。
