The interfacial effect in mixed-dimensional van der Waals heterostructure can improve the performance of terahertz (THz) components, such as THz emitter and THz modulator, which highlight the development of THz technology. However, this improvement has only been demonstrated in heterostructure based on graphene or small bandgap two-dimensional materials. We present the enhancement for THz generation and modulation from Si by insulating hexagonal boron nitride (h-BN) layer coating. The surface adsorption charges and the interface trapped charges lower the Fermi energy on Si surface, leading to an enlarged built-in electric field. Consequently, THz generation from h-BN/Si demonstrated significant enhancement compared with that by bare Si surface. Furthermore, the enlarged built-in electric field separates the interface photocarriers and reduces the surface recombination rate. The resulting dense charge accumulation raises up the photoconductivity after optical illumination and the enhanced THz modulation at h-BN/Si interface is approximately ten times higher than that by Si surface. These results not only present an efficient THz generation and modulation from the h-BN/Si interface but also pave the way for the deep understanding of interfacial effect in mixed-dimensional van der Waals heterostructures.

中文翻译：

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六方氮化硼/硅混合维范德华异质结构中太赫兹产生和调制的界面诱导增强

混合维范德华异质结构中的界面效应可以提高太赫兹（THz）组件的性能，例如太赫兹发射器和太赫兹调制器，这突出了太赫兹技术的发展。然而，这种改进仅在基于石墨烯或小带隙二维材料的异质结构中得到证明。我们通过绝缘六方氮化硼 (h-BN) 层涂层展示了对来自 Si 的太赫兹生成和调制的增强。表面吸附电荷和界面俘获电荷降低了硅表面的费米能，导致内建电场增大。因此，与裸硅表面相比，h-BN/Si 产生的太赫兹显着增强。此外，增大的内置电场使界面光载流子分离并降低了表面复合率。由此产生的密集电荷积累提高了光照射后的光电导率，并且 h-BN/Si 界面处增强的太赫兹调制比 Si 表面高出大约十倍。这些结果不仅展示了 h-BN/Si 界面的有效太赫兹生成和调制，而且为深入理解混合维范德华异质结构中的界面效应铺平了道路。