Semiconducting pyrite (cubic-FeS₂) is of great interest for photovoltaics, energy-storage and catalysis applications due its remarkable optical, electrochemical and catalytic properties in combination with its high abundance, low raw material cost and environmental benignancy. In addition, recent theoretical studies indicate that it is possible to synthesize two-dimensional (2D) FeS₂ with atomic thickness, and 2D FeS₂ possesses highly tunable electronic and magnetic properties that do not exist in its bulk form, enabling its application in nanoelectronics. Herein, we report the first growth of single-phase FeS₂ on SiO₂ substrates at temperatures between 300 °C and 600 °C by atmospheric pressure chemical vapor deposition (CVD). The temperature-dependent growth studies suggest that air-stable FeS₂ crystals with 2D morphologies grow at 450 °C and above while smaller irregular-shaped FeS₂ with low crystallinity and poor stability form at lower temperatures. We also demonstrate the patterned growth of 2D hexagonal crystals on SiO₂ substrates using graphene as a template at 600 °C. Raman spectroscopy measurements in conjunction with ab initio density functional theory (DFT) calculations confirm that the growth up to 600 °C does not include any other phase than FeS₂. Moreover, we show that laser-induced local phase transformations from FeS₂ (pyrite phase) and FeS (troilite phase) can be monitored in-situ by the changes in Raman spectra. Our method paves the way toward scalable synthesis of phase-pure FeS₂ crystals on SiO₂ substrates, which is fully compatible with semiconductor processing. This method can be also further developed and adopted for the synthesis of atomically thin 2D FeS₂ layers and their heterostructures with graphene that may bring enhanced or novel properties.

中文翻译：

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SiO ₂ †上黄铁矿的化学气相沉积和相稳定性

半导体黄铁矿（cubic-FeS ₂）由于其卓越的光学，电化学和催化性能以及高丰度，低原材料成本和环境友好性，在光伏，储能和催化应用中引起了极大的兴趣。另外，最近的理论研究表明，可以合成具有原子厚度的二维（2D）FeS ₂，并且2D FeS ₂具有高度可调的电子和磁性质，而其体积形式不存在，因此可以在纳米电子学中应用。在此，我们报道了单相FeS ₂在SiO ₂上的首次生长通过大气压化学气相沉积（CVD）在300°C和600°C之间的温度下处理基材。温度依赖性的生长研究表明，具有2D形态的空气稳定的FeS ₂晶体在450°C和更高温度下生长，而较小的不规则形状的FeS ₂具有较低的结晶度和较差的稳定性，在较低的温度下会形成。我们还演示了在600°C下使用石墨烯作为模板在SiO ₂衬底上二维六角形晶体的图案生长。拉曼光谱测量与从头算密度泛函理论（DFT）的计算相结合，证实了在600°C的温度下，除FeS ₂以外，不包括任何其他相。。此外，我们表明可以通过拉曼光谱的变化原位监测FeS ₂（黄铁矿相）和FeS（三菱铁矿相）的激光诱导的局部相变。我们的方法为在SiO ₂衬底上可扩展合成纯FeS ₂晶体铺平了道路，这与半导体工艺完全兼容。该方法还可以进一步开发和采用，以合成原子薄的2D FeS ₂层及其与石墨烯的异质结构，从而带来增强的或新颖的性能。