Sakakibara Ryotaro, Hirata Kaito, Takahashi Yasufumi, Norimatsu Wataru, Miyata Yasumitsu
Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan.
Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan.
Nano Lett. 2025 Aug 27;25(34):12851-12858. doi: 10.1021/acs.nanolett.5c02492. Epub 2025 Aug 6.
Engineering thermal strain is crucial for tuning the properties and functionalities of transition metal dichalcogenides (TMDs). Thermal strain arises from the thermal expansion coefficient (TEC) mismatch between TMDs and substrates, but conventional substrates often induce inhomogeneous broadening in the electronic structure, mainly due to surface roughness and charged impurities. Here, we demonstrate uniform thermal strain in monolayer WSe via van der Waals epitaxy on graphene/SiC(0001) substrates. Compared to WSe grown on graphite, its photoluminescence peaks show a redshift and line width narrowing of about 30%. These results suggest that uniform tensile strain is introduced to WSe due to the small TEC of SiC, and interfacial graphene suppresses the inhomogeneous broadening. Furthermore, tensile-strained monolayer MoS grown on graphene/SiC exhibits enhanced catalytic activity for the hydrogen evolution reaction. Our findings highlight the potential of the graphene/SiC substrate as a platform for improved strain engineering in TMDs, enabling future applications in electronics, optoelectronics, and electrocatalysis.
工程热应变对于调节过渡金属二硫属化物（TMDs）的性质和功能至关重要。热应变源于TMDs与衬底之间的热膨胀系数（TEC）不匹配，但传统衬底通常会在电子结构中引起不均匀展宽，这主要是由于表面粗糙度和带电杂质。在此，我们通过在石墨烯/SiC(0001)衬底上进行范德华外延，证明了单层WSe中的均匀热应变。与生长在石墨上的WSe相比，其光致发光峰出现红移，线宽变窄约30%。这些结果表明，由于SiC的热膨胀系数小，向WSe引入了均匀的拉伸应变，并且界面石墨烯抑制了不均匀展宽。此外，生长在石墨烯/SiC上的拉伸应变单层MoS对析氢反应表现出增强的催化活性。我们的研究结果突出了石墨烯/SiC衬底作为TMDs中改进应变工程平台的潜力，为未来在电子学、光电子学和电催化方面的应用提供了可能。
