Monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) show interesting optical and electrical properties because of their direct bandgap. However, the low absorption of atomically thin TMDs limits their applications. Here, we report enhanced absorption and optoelectronic properties of monolayer molybdenum disulfide (MoS₂) by using an asymmetric Fabry–Perot cavity. The cavity is based on a hybrid structure of MoS₂/ hexagonal boron nitride (BN)/Au/SiO₂ realized through layer-by-layer vertical stacking. Photoluminescence (PL) intensity of monolayer MoS₂ is enhanced over 2 orders of magnitude. Theoretical calculations show that the strong absorption of MoS₂ comes from photonic localization on the top of the microcavity at optimal BN spacer thickness. The n/n⁺ MoS₂ homojunction photodiode incorporating this asymmetric Fabry–Perot cavity exhibits excellent current rectifying behavior with an ideality factor of 1 and an ultrasensitive and gate-tunable external photo gain and specific detectivity. Our work offers an effective method to achieve uniform enhanced light absorption by monolayer TMDs, which has promising applications for highly sensitive optoelectronic devices.

中文翻译：

---

基于混合二维材料的超灵敏可调光电二极管中的法布里-珀罗腔增强光学吸收

单层二维（2D）过渡金属二硫化碳（TMD）由于其直接带隙而显示出令人感兴趣的光学和电学性质。但是，原子级薄TMD的低吸收性限制了它们的应用。在这里，我们报道了通过使用不对称的Fabry-Perot腔增强了单层二硫化钼（MoS ₂）的吸收和光电性能。该腔体基于通过逐层垂直堆叠实现的MoS ₂ /六方氮化硼（BN）/ Au / SiO ₂的混合结构。单层MoS _2的光致发光（PL）强度提高了2个数量级。理论计算表明，MoS ₂的强吸收来自于在最佳BN间隔层厚度下微腔顶部的光子定位。结合了这种不对称的Fabry-Perot腔的n / n ⁺ MoS ₂同质结光电二极管具有出色的电流整流性能，理想因子为1，并且具有超灵敏和栅极可调的外部光增益和比检测能力。我们的工作提供了一种有效的方法，可通过单层TMD来实现均匀增强的光吸收，这对于高灵敏度的光电器件具有广阔的应用前景。