本研究报道了二维半导体存在一种缺陷束缚带边态 (defect-bound band edge, DBBE)，对缺陷电离和载流子输运影响显著。来自吉林大学集成光电子国家重点实验室的李贤斌教授领导的团队，以单层MoS₂为例，使用第一性原理计算证实了缺陷束缚带边态的存在及其对载流子传输的潜在影响。他们发现形成缺陷束缚带边态的原因是带电缺陷和激发载流子之间存在强束缚作用。该强束缚作用是维度降低的结果，也是二维材料中电荷屏蔽减弱的结果。载流子激发到缺陷束缚带边态所需能量低于形成自由载流子的所需能量，并且位于DBBE态的载流子可以在适当浓度下通过波函数重叠提供传输通道。该传输机制可能是实验观测的二维材料电导的潜在机制。他们的研究揭示了二维半导体中载流子的杂质电离和传输的全新物理图像，对设计新兴纳米电子器件具有重要影响。

There exists a defect-bound band edge (DBBE) state in 2D semiconductors, which has a significant effect on defectionization and carrier transport. A team led by Professor Li Xianbin from the State Key Laboratory of Integrated Optoelectronics of Jilin University used first-principles calculations to verify the existence of DBBE state in single-layer MoS2, an example for 2D semiconductor, and its potential impact on carrier transport. They found that the reason for the formation of DBBE states is strong binding between charged defect and excited carrier. The strong binding is a result of the spatial confinement as well as the reduced screening in 2D materials. The energy required to excite the carrier to DBBE state is lower than the energy required to form the free carrier, and the carriers in DBBE state can provide a transmission channel by wave function overlap at an appropriate concentration. This transport may be a potential mechanism for experimentally observed 2D material conductance. Their research reveals a new physical image of ion ionization and carrier transport in 2D semiconductors, which has an important impact on the design of emerging nanoelectronic devices.