金属-二维材料-金属是最常见的二维材料光探测器件的结构。由于结构简单、易于集成，该类器件受到最广泛的关注和研究。其自驱动光探测的模式具有很低的暗电流，有望成为高性能红外探测的新途径。然而金属-二维材料-金属的自驱动光探测存在两个瓶颈问题：（1）反对称的金属-二维材料结区引起的泛光照射下光响应的抵消；（2）二维材料有限光吸收导致的低响应率。文中介绍了利用等离激元纳米结构的非对称集成引入非对称的光耦合，从而打破泛光照射下二维材料与两端电极接触区域产生的光电流的对称性，实现净的自驱动光响应；同时利用等离激元纳米结构产生的局域强光场提高二维材料光吸收率和光响应率的一系列研究进展。在石墨烯等离激元纳米谐振腔复合结构中，实现两个电极附近的光响应对比度超过100倍，突破了对称光耦合导致的光响应抵消的难题。由于具有将入射光耦合成局域模式的优越能力，等离激元纳米谐振腔比亚波长金属光栅更有效地提高石墨烯响应率一个数量级以上。

Metal-2D material-metal photodetectors is the most common type of 2D material photodetectors. Due to the simple structure and the ease of integration with other systems, metal-2D material-metal photodetectors have received the widest range of attentions and research interest. The self-driven mode of this type of photodetectors has very low dark current, and then it is regarded as a promising new route for high performance infrared detection. However, there are two bottleneck problems for self-driven metal-2D material-metal photodetectors: (1) photoresponse cancellation caused by antisymmetric 2D material-contact junctions, (2) low responsivity due to limited light absorption of 2D materials. The recent progress on the study of metal-2D material-metal photodetectors with asymmetrically integrated plasmonic nanostructures was introduced, where asymmetrical light coupling was utilized to break the anti-symmetry between the photocurrents at the two contact-2D material junctions for self-driven net photoresponse, and the induced strong local field was utilized to enhance the absorptance and the responsivity of the 2D material. In the hybrid device of graphene and plasmonic nanocavities, the contrast between photoresponses at the two contacts is more than 100 times, which breaks through the problem of photoresponse cancellation caused by symmetric optical coupling. Due to the superior capability to couple the incident light into a localized mode, the plasmonic nanocavity can enhance the responsivity of graphene over one order of magnitude higher than a subwavelength metal grating.