Cui Shumao, Pu Haihui, Wells Spencer A, Wen Zhenhai, Mao Shun, Chang Jingbo, Hersam Mark C, Chen Junhong
Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA.
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
Nat Commun. 2015 Oct 21;6:8632. doi: 10.1038/ncomms9632.
Two-dimensional (2D) layered materials have attracted significant attention for device applications because of their unique structures and outstanding properties. Here, a field-effect transistor (FET) sensor device is fabricated based on 2D phosphorene nanosheets (PNSs). The PNS sensor exhibits an ultrahigh sensitivity to NO2 in dry air and the sensitivity is dependent on its thickness. A maximum response is observed for 4.8-nm-thick PNS, with a sensitivity up to 190% at 20 parts per billion (p.p.b.) at room temperature. First-principles calculations combined with the statistical thermodynamics modelling predict that the adsorption density is ∼10(15) cm(-2) for the 4.8-nm-thick PNS when exposed to 20 p.p.b. NO2 at 300 K. Our sensitivity modelling further suggests that the dependence of sensitivity on the PNS thickness is dictated by the band gap for thinner sheets (<10 nm) and by the effective thickness on gas adsorption for thicker sheets (>10 nm).
二维（2D）层状材料因其独特的结构和优异的性能而在器件应用中备受关注。在此，基于二维黑磷纳米片（PNS）制备了一种场效应晶体管（FET）传感器器件。该PNS传感器在干燥空气中对NO₂表现出超高灵敏度，且灵敏度取决于其厚度。对于4.8纳米厚的PNS，观察到最大响应，在室温下20十亿分之一（ppb）时灵敏度高达190%。第一性原理计算结合统计热力学模型预测，当在300K下暴露于20 ppb NO₂时，4.8纳米厚的PNS的吸附密度约为10¹⁵ cm⁻²。我们的灵敏度模型进一步表明，灵敏度对PNS厚度的依赖性，对于较薄的片材（<10纳米）由带隙决定，对于较厚的片材（>10纳米）由气体吸附的有效厚度决定。
