Strong electronic interactions can result in novel particle–antiparticle (electron–hole, e–h) pair generation effects¹, which may be exploited to enhance the photoresponse of nanoscale optoelectronic devices. Highly efficient e–h pair multiplication has been demonstrated in several important nanoscale systems, including nanocrystal quantum dots^2,3,4,5,6, carbon nanotubes^7,8,9 and graphene^10,11,12,13. The small Fermi velocity and nonlocal nature of the effective dielectric screening in ultrathin layers of transition-metal dichalcogenides (TMDs) indicates that e–h interactions are very strong^14,15,16, so high-efficiency generation of e–h pairs from hot electrons is expected. However, such e–h pair multiplication has not been observed in 2D TMD devices. Here, we report the highly efficient multiplication of interlayer e–h pairs in 2D semiconductor heterostructure photocells. Electronic transport measurements of the interlayer I–V_SD characteristics indicate that layer-indirect e–h pairs are generated by hot-electron impact excitation at temperatures near T = 300 K. By exploiting this highly efficient interlayer e–h pair multiplication process, we demonstrate near-infrared optoelectronic devices that exhibit 350% enhancement of the optoelectronic responsivity at microwatt power levels. Our findings, which demonstrate efficient carrier multiplication in TMD-based optoelectronic devices, make 2D semiconductor heterostructures viable for a new class of ultra-efficient photodetectors based on layer-indirect e–h excitations.

强大的电子相互作用可以产生新颖的粒子-反粒子（电子-空穴，e-h）对生成效应¹，可以利用这种效应来增强纳米级光电器件的光响应。在几个重要的纳米级系统中已经证明了高效的e–h对倍增，包括纳米晶体量子点^{2、3、4、5、6}，碳纳米管^7、8、9和石墨烯^{10、11、12、13}。小费米速度和过渡金属二卤化钨（TMDs）超薄层中有效介电筛选的非局部性质表明，e–h相互作用非常强^14,15,16，因此期望从热电子高效生成e–h对。但是，在二维TMD设备中尚未观察到这种e–h对乘法。在这里，我们报告了二维半导体异质结构光电池中层间h–h对的高效倍增。中间层的电子输运测量I-V _SD特征表明层间接E-H对由热电子碰撞激发以接近的温度下产生Ť = 300K。通过利用这种高效的层间e-h对倍增过程，我们演示了在微瓦功率水平下显示出350％的光电响应性增强的近红外光电器件。我们的发现证明了在基于TMD的光电器件中有效的载流子倍增，使得2D半导体异质结构对于基于层间接e-h激发的新型超高效光电探测器是可行的。