Zou Zixing, Liang Junwu, Zhang Xuehong, Ma Chao, Xu Pan, Yang Xin, Zeng Zhouxiaosong, Sun Xingxia, Zhu Chenguang, Liang Delang, Zhuang Xiujuan, Li Dong, Pan Anlian
Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, School of Physics and Electronics, and State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, Hunan 410082, P.R. China.
School of Physics and Telecommunication Engineering, Yulin Normal University, Yulin, Guangxi 537000, P.R. China.
ACS Nano. 2021 Jun 22;15(6):10039-10047. doi: 10.1021/acsnano.1c01643. Epub 2021 May 26.
van der Waals (vdW) vertical p-n junctions based on two-dimensional (2D) materials have shown great potential in flexible, self-driven, high-efficiency electronic and optoelectronic applications. However, due to the complex nucleation dynamics, the controllable synthesis of vertical heterostructures remains a daunting challenge. Here, we report the controlled growth of vertical GaSe/MoS p-n heterojunctions a liquid gallium (Ga)-assisted chemical vapor deposition method. The growth mechanism can be interpreted by theoretical calculations based on the Burton-Cabrera-Frank theory. By analyzing the diffusion barriers and the Ehrlich-Schwoebel barriers of adatoms, we found that the growth modes between vertical and lateral can be precisely switched by means of adjusting the amount of Ga. Based on the achieved high-quality vertical GaSe/MoS p-n heterojunctions, photosensing devices are further designed and systematically investigated. Upon light illumination, prominent photovoltaic effects with large open-circuit voltage (0.61 V) and broadband detection capability from 375 to 633 nm are observed, which can further be employed for self-powered photodetection with high responsivity (900 mA/W) and fast response speed (5 ms). The developed liquid-metal-assisted strategy provides an effective method for controllable synthesis of vdW heterostructures and will give impetus to their applications in high-performance optoelectronic device.
基于二维（2D）材料的范德华（vdW）垂直p-n结在柔性、自驱动、高效电子和光电子应用中显示出巨大潜力。然而，由于复杂的成核动力学，垂直异质结构的可控合成仍然是一项艰巨的挑战。在此，我们报告了通过液镓（Ga）辅助化学气相沉积法可控生长垂直GaSe/MoS p-n异质结。生长机制可以通过基于伯顿-卡布雷拉-弗兰克理论的理论计算来解释。通过分析吸附原子的扩散势垒和埃利希-施沃贝尔势垒，我们发现垂直和横向生长模式可以通过调节Ga的量来精确切换。基于所制备的高质量垂直GaSe/MoS p-n异质结，进一步设计并系统研究了光传感器件。在光照下，观察到具有大开路电压（0.61 V）的显著光伏效应和从375到633 nm的宽带检测能力，这可进一步用于具有高响应度（900 mA/W）和快速响应速度（5 ms）的自供电光电探测。所开发的液态金属辅助策略为vdW异质结构的可控合成提供了一种有效方法，并将推动其在高性能光电器件中的应用。
