低噪声、宽谱响应的碳纳米管薄膜-石墨烯复合光探测器

Hybrid CNT Film-Graphene Photodetectors with Low Noise and Broadband

采用高纯半导体碳纳米管薄膜和石墨烯构建复合结构光探测器,研究其光电响应特性。结果表明,在光照下,顶层石墨烯中的光生载流子通过碳纳米管与石墨烯之间薄的非晶硅层,隧穿至底层的碳纳米管薄膜中,在非晶硅层两侧分别富集电子和空穴,形成光致栅压(Photogating),有效地改变了碳纳米管薄膜晶体管的电流。器件在可见光(633 nm)条件下得到响应度为83 m A/W,并在近红外波段范围内仍保持好的光响应特性。由于石墨烯具有宽谱光吸收特性,半导体碳纳米管薄膜晶体管具有小的暗电流,碳纳米管–石墨烯复合光探测器发挥了两种材料的优势,为今后高性能宽谱光电探测器的制备奠定了基础。

Highly purified semiconducting carbon nanotube（CNT） thin films and graphene are used to fabricate hybrid photodetector. The results indicate that the hot carriers generated in graphene can tunnel into bottom CNT film through nanometer thick silicon film when illuminated. As a result, electrons and holes are accumulated at separated side of the silicon layer, resulting in a modulation of the current in the CNT film transistor due to the photogating effect. The photodetector shows a responsivity of 83 m A/W for visible light（633 nm） and a good response within the near-infrared range. Such CNT film-graphene photodetector, taking advantages of both broadband absorption of graphene and small dark current of semiconducting CNTs, paves the way to future high performance infrared photodetectors.