Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange
Tunable Sulfur Incorporation into Atomic Layer Deposition Films Using Solution Anion Exchange
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DOI：
10.1021/acs.chemmater.2c03773
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发表时间：
2023-03-17
影响因子：
8.6
通讯作者：
Dasgupta，Neil P.
中科院分区：
文献类型：
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作者：
Lenef，Julia D.;Gayle，Andrew J.;Dasgupta，Neil P.
通过原子层沉积（ALD）沉积的金属硫化物和氧硫化物薄膜是用于包括太阳能电池、催化剂和电子器件在内的一系列应用的重要功能材料。然而，含硫膜的ALD通常需要H2S，一种有毒、腐蚀性和易燃气体。为了规避这些挑战，我们提出了一种调整硫掺入ALD膜的方法，首先生长金属氧化物，使用CuOx作为模型系统，然后通过溶液相硫阴离子交换过程。通过控制反应时间，溶液的摩尔浓度和温度，我们证明了可调的硫掺入到薄膜中，这是使用耦合的反应扩散模型描述。的膜的结晶度，组成和形态的演变进行了量化的阴离子交换工艺参数的函数。示出了在ZnO@TiO2@CuO核-壳-壳纳米线上的共形阴离子交换，证明了在高纵横比结构上保持初始ALD工艺的共形性的能力。此外，在微图案化基底上进行区域选择性阴离子交换，说明了器件制造的途径。最后，转换后的薄膜的电性能进行了评估，表明高达4个数量级的薄层电阻的可调减少。在未来，ALD和阴离子交换化学的组合可用于在不需要H2S气体的情况下掺入硫，同时保持原始ALD工艺的原子精确性和保形性。
Metal sulfide and oxysulfide thin films deposited by atomic layer deposition (ALD) are important functional materials for a range of applications including solar cells, catalysts, and electronic devices. However, ALD of sulfur-containing films typically requires H2S, a toxic, corrosive, and flammable gas. To circumvent these challenges, we propose a method of tuning sulfur incorporation into ALD films by first growing a metal oxide, using CuOxas a model system, followed by a solution-phase sulfur anion-exchange process. By controlling the reaction time, solution molarity, and temperature, we demonstrate tunable sulfur incorporation into the films, which is described using a coupled reaction-diffusion model. The evolution of the film crystallinity, composition, and morphology was quantified as a function of the anion-exchange process parameters. Conformal anion exchange on a ZnO@TiO2@CuO core–shell–shell nanowire is shown, demonstrating the ability to maintain the conformality of the initial ALD process on high-aspect-ratio structures. Additionally, area-selective anion exchange was performed on micro-patterned substrates, illustrating a pathway toward device fabrication. Finally, the electrical properties of the converted films were evaluated, indicating a tunable reduction in sheet resistance of up to 4 orders of magnitude. In the future, the combination of ALD and anion-exchange chemistry can be used to incorporate sulfur without the need for H2S gas, while maintaining the atomically precise and conformal properties of the original ALD process.