IV-V族二维半导体器件电子输运机理与性能调控

Owing to the ultrathin nanostructure, unique electronic structure, and quantum confinement effect, two-dimensional (2D) semiconductor materials are promising candidates to be served as nanoelectronic device with ultrahigh performance and ultralow power consumption. Recent experimental measurements have demonstrated that two-dimensional group IV-V semiconductors possess excellent stability and anisotropic transport properties, revealing the great potentials of these semiconductors in the field of electronic devices. Correspondingly, there is an urgent need to understand the electron transport mechanism and the modulation of transport performance of the two-dimensional IV-V semiconductor devices. In order to address this issue, we plan to carry out numerical simulation based on the density functional theory that treating physical model quantum-mechanically, which is combined with non-equilibrium Green's function to study the fundamental properties related to electron transport through the nanodevice. We will analyze the physical mechanism of van der Waals contact and channel doping on the device performance of electron transport. In addition, this research is also devoted to uncover the interaction influences of the two modulation methods on the electronic properties of nanodevice, thus allowing us to accurately control the electron transport properties of 2D semiconductor devices. Our investigations are expected to generate a parameter system referred to electron transport properties that can be optimized and improved by using van der Waals heterostructures and surface adsorption doping, and the modeling method for accurate and fast prediction of transport properties of 2D layered group IV-V semiconductor devices will be furtherly developed. Our research results could provide theoretical fundamentals to the computational designs and practical applications of group IV-V layered nanomaterial-based nanodevices.

二维层状半导体因其超薄的物理结构、独特的电子结构和量子限域效应，成为超高性能和超低功耗电子器件的理想材料。最新实验研究表明，IV-V族二维半导体具有优异的稳定性和各向异性输运性质，在电子器件领域有巨大的应用前景。因此，阐明器件电子输运机理并有效调控输运性能成为亟待解决的问题。本项目拟采用量子力学密度泛函理论结合非平衡格林函数数值计算方法，研究IV-V族二维半导体器件电子输运机理与性能调控，分析和阐明不同范德华界面接触和沟道表面吸附对二维半导体器件电子输运性能调控的物理机制，揭示上述两种手段有机结合时的相互影响及其对器件电子输运的调制机理，优化结构以实现对二维半导体器件输运性能的精准调控。本项目将探索建立包含范德华异质结和沟道表面吸附的参数控制体系来优化器件输运性能，进一步发展IV-V族二维半导体电子器件输运性能的快速准确预测方法，研究结果可为IV-V族层状材料器件设计和应用提供理论依据。

二维层状半导体因其超薄的二维物理结构和独特的电子结构，成为超高性能、超低功耗电子器件的理想材料。最近实验上制备的IV-V族二维半导体具有优异的稳定性和强各向异性输运性质，因此该系列半导体在电子器件领域具有巨大的应用前景。本项目采用密度泛函理论结合非平衡格林函数的数值计算方法，系统地研究和模拟计算了四种单层半导体的输运性质，探索了IV-V族二维半导体器件载流子输运性能的调控机制，设计了基于二维IV-V半导体的场效应晶体管器件。分析了不同范德华接触对二维半导体器件电子输运性能调控的物理机制，发现石墨烯和二维GeP半导体的接触后出现显著的电荷转移和降低器件功耗，石墨烯电极高效注入载流子到二维半导体沟道，从物理机制上阐明了石墨烯作为电极对器件输运性能的影响，提出基于石墨烯的金属半导体接触的高性能器件设计方案。研究发现铜和镍金属界面接触与二维半导体形成良好的轨道交叠，引起了强烈的电荷注入，提出了基于铜和镍接触的器件优化方案。分析了不同分子基团表面吸附前后器件电子结构性质的变化，探索了不同基团、不同位置表面吸附掺杂对电子结构改性的内在机制，发现单层SiAs半导体对于二氧化氮分子吸附非常敏感，引起强烈的电荷转移和功函变化，设计了基于SiAs半导体的气体传感器件。探索了几种典型的点缺陷结构，包括替位缺陷、反位缺陷、空位缺陷、取代掺杂四种，对半导体的电子结构和载流子输运性能的影响机制，发现空位缺陷在费米能级附近引入了扩展态，有利于提升载流子输运性质并降低工作电压，综合运用栅压调控沟道区域的载流子浓度使得器件的亚阈值摆幅接近国际半导体路线图2027规划需求。研究发现二维IV-V层状材料具有良好力学性质和各向异性电学性质，电流随着应力的增加而增加，在较小的拉伸应力作用下电流显著增加百分之五十，设计了新型应力传感器；分析了石墨烯与二维半导体的耦合机制，理清了金属半导体接触对输运性能的影响机制，提出采用柔性石墨烯电极方案进一步降低工作电压。