悬空纳米结构的六氮五铌薄膜太赫兹检测器研究

THz detectors are key components in real-time terahertz imaging and terahertz wireless communication. Micron size of the room temperature microbolometer is proved to be easy to integration and fabricate array with relative high sensitivity, but in practical application is limited by its response speed and sensitivity. In order to achieve high-speed sensitive detection of terahertz signal, this study presents the preparation of Nb5N6 film nanowire nanobolometer. Air-suspended Nb5N6 nanobolometers with different sizes are going to be fabricated by electron beam lithography and reactive ion etching technique. The relationship between the size and the performance of the devices will be discussed in details. In addition, electrothermal model is constructed for air-suspended Nb5N6 nanobolometer to analyze the numerical relationship between the thermal conductivity and the size of the suspended nanowires, and theoretically analyze the relationship between the device size and the performance parameters of the device. These studies are helpful to enhance mutual understanding of terahertz detection mechanism of Nb5N6 nanobolometer, breakthrough device sensitivity and response speed bottleneck, and the preparation of more large-scale array device, expansion device application field and promote the practical devices.

太赫兹探测器是太赫兹实时成像和太赫兹无线通讯的关键部件。本课题提出采用悬空结构的六氮五铌薄膜纳米线nanobolometer,以实现高速灵敏的太赫兹检测器。通过深入研究悬空结构的六氮五铌薄膜纳米线nanobolometer的制备与性能表征，结合悬空纳米结构电热模型，探讨其太赫兹响应的物理机理及由尺寸效应带来的对器件的电压响应率、噪声以及响应时间的影响。这对进一步理解太赫兹波与六氮五铌薄膜纳米线的相互作用机理，提高器件灵敏度同时缩短响应时间至关重要，也是制备更大规模阵列器件、扩展器件应用领域和推进器件实用化的基础。

研制了悬空纳米结构的六氮五铌薄膜太赫兹检测器，包括六氮五铌薄膜，纳米制备工艺，悬空结构工艺，太赫兹平面天线研究，器件电热模型分析，器件测试表征等。采用电子束曝光等先进微纳米加工手段，将六氮五铌薄膜加工成纳米线，集成平面天线和硅透镜等，制备成准光耦合的六氮五铌薄膜太赫兹探测接收机，悬空桥尺寸达到0.8 μm× 0.4 μm。在0.65 THz, 探测器的等效噪声功率(NEP)达到了10 pW/√Hz，响应时间为12.5 µs，项目负责人掌握了研制悬空纳米结构的六氮五铌薄膜太赫兹检测器件的核心技术，为高灵敏度都太赫兹阵列探测与成像奠定了基础。基于以上研究，在国际著名期刊Appl. Phys. Lett.等发表论文17篇，其中SCI论文16篇，中文杂志1篇；有关太赫兹探测器的研究论文分别入选Optics Express杂志 Editor's Pick和获2019年度中国激光杂志主编推荐奖；申请国家发明专利12项，已获得授权7项，完成了项目的预期研究目标和成果。