Nanostructured transition metal dichalcogenides (TMDs) like MoS₂ hold promise for gas sensing applications due to their exceptional properties. However, limitations exist in maximizing sensor performance, such as limited active sites for gas interaction and sluggish response/recovery times. This study explores swift heavy ion (SHI) irradiation as a strategy to address these challenges in MoS₂-based NO₂ gas sensors. MoS₂ nanoflakes were fabricated and subsequently irradiated with 120 MeV silver (Ag) ions to induce structural and morphological modifications. Characterization techniques confirmed the formation of Mo and S vacancies within the MoS₂ lattice due to irradiation. Significantly, SHI irradiation resulted in a remarkable enhancement of approximately 3 times improvement in sensing response compared to pristine MoS₂ sensors. Additionally, the irradiated sensors exhibit substantial improvements in both response and recovery times for NO₂ detection. SHI irradiation resulted in the formation of self-affine nanostructures and increased grain fragmentation as fluence rises. This enhanced surface area is hypothesized to promote gas-sensor response. To gain deeper insights into the underlying mechanism, first-principles calculations were employed. These calculations suggest that electron transfer occurs from the MoS₂ surface to the NO₂ molecule during interaction. Furthermore, the irradiation-induced vacancies facilitate stronger NO₂ adsorption on the MoS₂ surface compared to the pristine sample. This work demonstrates the effectiveness of SHI irradiation in engineering defects within MoS₂ nanoflakes, leading to significantly improved NO₂ gas-sensing performance. This approach offers a promising avenue for developing next-generation TMD-based gas sensors with enhanced sensitivity, response times, and stability.

中文翻译：

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通过快速重离子辐照增强纳米晶 MoS2 中的 NO2 气体传感：实验和 DFT 研究


MoS₂ 等纳米结构过渡金属硫化物 （TMD） 因其卓越的性能而有望用于气体传感应用。然而，在最大限度地提高传感器性能方面存在局限性，例如气体相互作用的活性位点有限和响应/恢复时间缓慢。本研究探讨了快速重离子 （SHI） 照射作为解决基于 MoS₂ 的 NO₂ 气体传感器中这些挑战的策略。制备了 MoS₂ 纳米薄片，随后用 120 MeV 银 （Ag） 离子照射以诱导结构和形态修饰。表征技术证实了由于辐照，MoS₂ 晶格内形成了 Mo 和 S 空位。值得注意的是，与原始的 MoS₂ 传感器相比，SHI 照射导致传感响应显着提高约 3 倍。此外，辐照传感器在 NO₂ 检测的响应和恢复时间方面都表现出显著改善。SHI 辐照导致自仿射纳米结构的形成，并随着通量的增加而增加晶粒碎裂。假设这种增强的表面积可以促进气体传感器响应。为了更深入地了解潜在机制，采用了第一性原理计算。这些计算表明，电子在相互作用过程中从 MoS₂ 表面转移到 NO₂ 分子。此外，与原始样品相比，辐照诱导的空位有助于 NO₂ 在 MoS₂ 表面上更强的吸附。 这项工作证明了 SHI 辐照对 MoS₂ 纳米薄片内工程缺陷的有效性，从而显着提高了 NO₂ 气敏性能。这种方法为开发具有更高灵敏度、响应时间和稳定性的下一代基于 TMD 的气体传感器提供了一条有前途的途径。