宽光谱、高灵敏度、低功耗石墨烯图像传感器研究

With the development of the industrial intelligence and internet of things technology, image sensors have been widely used, and the enhancement of their performances is of great practical significance and broad market prospects. At present, commercial image sensors have met bottlenecks in spectral width, sensitivity and power consumption, which limit their versatility in imaging fields and increase the imaging cost. Developing new photosensitive materials as well as new broad-spectrum, high-sensitivity and low-power photodetector based on them are reasonable choices to break through the bottlenecks. This project is devoted to developing a wide spectrum, high sensitivity and low power graphene image sensor. On the one hand, the wide spectrum photoresponse of graphene is fully utilized. On the other hand, an asymmetric structure of electrodes is introduced to eliminate the dark current, and a titanium dioxide protective layer is introduced to improve the sensitivity and stability of the device. Furthermore, a CMOS-compatible process is developed to integrate the graphene photodetector array with the silicon CMOS circuits used for amplifying the photocurrent signal, leading to a high-performance graphene image sensor. The successful implementation of this project will break through the bottleneck faced by image sensors in the current stage in terms of versatility, explore new application fields of graphene materials, and provide new ideas for the development of three-dimensional photoelectric integrated chips.

随着工业智能化和物联网技术的发展，图像传感器得到了广泛应用，其性能的提升将产生巨大的现实意义，具有广阔的市场前景。目前商用图像传感器在光响应谱宽、灵敏度和功耗等方面性能的提升上存在瓶颈，限制了其在成像领域中的通用性，增加了成像成本。开发新型光敏材料并研制出基于新材料的宽光谱、高灵敏度、低功耗光电探测器是突破图像传感器发展瓶颈的必然选择。本项目致力于研发出宽光谱、高灵敏度、低功耗石墨烯光电探测器，一方面充分利用石墨烯材料宽谱响应特性，另一方面引入非对称结构电极消除器件暗电流，引入二氧化钛保护层提高器件灵敏度和稳定性。更进一步，开发CMOS兼容后工艺将石墨烯光电探测器阵列和用于光电流信号放大的硅CMOS电路三维集成，最终研制出高性能石墨烯图像传感器。本课题的顺利实施，将突破现阶段图像传感器在成像通用性方面所面临的瓶颈，开拓石墨烯材料新型应用领域，同时为三维光电集成芯片的发展提供新思路。

随着工业智能化和智能物联网技术的发展，图像传感器得到了广泛应用，其性能的提升将产生巨大的现实意义，具有广阔的市场前景。目前商用图像传感器在光响应谱宽、灵敏度和功耗等方面性能的提升上存在瓶颈，限制了其在成像领域中的通用性，增加了成像成本。开发新型光敏材料并研制出基于新材料的宽光谱、高灵敏度光电探测器是突破图像传感器发展瓶颈的必然选择。本项目致力于研发出宽光谱、高灵敏度、低功耗石墨烯光电探测器，一方面充分利用石墨烯材料宽谱响应特性，另一方面引入量子点和半导体材料，提高器件光响应度。本项目研制出高稳定性、高响应度石墨烯/硅异质结光探测器，白光照射下，光响应度可达5*10^6A/W。该工作的创新之处是在器件制作过程中，未去除石墨烯表面的PMMA层，这样可以避免石墨烯和光刻胶接触，减小工艺过程对石墨烯造成的损伤。保留PMMA层，相当于对石墨烯器件进行了封装，避免了空气和石墨烯接触，从而提高了石墨烯光探测器的稳定性。本项目同时研制出高响应度紫外探测器，将TiO2量子点薄膜覆盖在单层CVD石墨烯表面，制备紫外探测器，其在365 nm波长下的响应度约为10^5 A/W，高紫外灵敏度受益于TIO2层的较强光吸收特性和光控氧吸附特性。在高性能石墨烯光探测器研究的基础上，我们设计了匹配的接收电路，为后续单片集成的石墨烯图像传感器的研制做了充分的准备。本项目的顺利实施，将突破现阶段图像传感器在微光成像方面所面临的瓶颈，开拓石墨烯材料新型应用领域，同时为三维光电集成芯片的发展提供新思路