石墨烯/宽禁带半导体异质结构光电特性及紫外光探测器研究

Graphene, other two-dimensional materials and hybrid systems have opened up bright approach for developing novel optoelectronic devices, thanking to the excellent optical and electrical properties. This project focus on graphene/widegap semiconductor heterostructures, and explore high-performance UV photodetectors. Based on the devices structure with the separated absorption and multiplication region, combining high carrier mobility and high transparency properties of graphene, selective absorption spectrum of wide gap semiconductors and carrier (exciton) separation capacity at the heterogeneous interface, we explore the practical UV photodetectors, moreover, the key problems such as the formation characteristics of graphene/widegap semiconductor heterostructures, energy band matching modulation, interface potential barrier fluctuation, and charge trapping. We also systematically study the role of an external electric field, such as interface energy band modulation, carriers (exciton) ionization, recombination, transport and amplification process, as well as the charge trapping switching. We develop the fabrication methods of heterostructures such as high quality graphene/wide gap semiconductors,and establish correlation models between device performance and the structure and technological parameters. Finally, it will be well developed for high-gain and high-speed UV photodetectors based on graphene/widegap semiconductors.

以石墨烯为代表的二维原子晶体及其复合结构的优异光电特性为发展新型光电子器件开辟了新的重要途径。本项目拟研究石墨烯/(无机和有机)宽禁带半导体异质结构光电特性，探索高性能紫外探测器应用。基于光吸收区与载流子倍增区分离的结构，利用石墨烯的高载流子迁移率和高透光性特点、宽禁带半导体材料的紫外光波段选择吸收及异质界面的载流子(激子)分离能力，探索发展可实用化的高性能紫外探测器，并依此深入研究该异质结构的形成特征、能带匹配调制、界面势垒涨落、电荷陷阱态控制等关键问题；系统研究外电场对界面能带调制、载流子(激子)离化、复合、输运与放大过程，以及电荷陷阱开关的影响规律；优化制备方法和工艺；研制获得具有高增益、高速的石墨烯/AlGaN宽禁带半导体、有机宽禁带半导体异质结构紫外探测器，为发展以石墨烯为代表的二维原子晶体在光电子器件上的应用提供科学依据和技术基础。

以石墨烯为代表的二维原子晶体及其复合结构的优异光电特性为发展新型光电子器件开辟了新的重要途径。本项目主要研究了石墨烯/宽禁带有机半导体异质结构制备及光电特性。基于光吸收区与载流子倍增区分离的结构，利用石墨烯的高载流子迁移率和范德华界面等特点、宽禁带有机半导体材料的紫外光波段选择吸收及异质界面的载流子(激子)分离能力，探索发展高性能紫外探测器，并深入研究该异质结构的形成特征、能带匹配调制等关键问题；同时，研究了新型二维材料及其异质结构的光电特性，研究外电场对界面能带调制、载流子输运过程，提出和实现了新的器件机制，包括一种新型的PN结击穿机制-弹道雪崩， 光电效应和光电热电效应增强光响应等，为发展以石墨烯为代表的二维原子晶体在光电子器件上的应用提供科学依据和技术基础。