State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinghuangdao 066004, China.
School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
Nanoscale. 2017 Feb 2;9(5):1916-1924. doi: 10.1039/c6nr08610a.
Two-dimensional chalcogenide monolayers are strong candidates for next-generation flexible and transparent optoelectronics. Due to the intrinsic ultrathin thickness and limited optical absorption, however, their responsivity is normally low. Here we develop a simple and low-cost method to fabricate high-performance hybrid phototransistors of monolayer WS with significantly enhanced responsivity and an extended spectral response range, by virtue of surface decoration with liquid-phase exfoliated SnS nanosheets (NSs). The hybrid phototransistors show a much enhanced responsivity of ∼2 A W and an ultrahigh light/dark signal-to-noise ratio of 10 under 457 nm excitation, exhibiting a significant increase of 3 orders of magnitude in responsivity and a 100 fold increase in signal-to-noise ratio, compared with pure WS devices. Our hybrid photodetectors also exhibit a respectable response speed, with a rise and decay time of 51 μs and 98 μs, respectively. After optimal surface decoration with narrow bandgap SnS NSs atop a monolayer WS channel, an emergent optical responsivity in the near infrared region (1064 nm) is also observed.
二维硫属化物单层是下一代柔性透明光电的有力候选材料。然而，由于其固有超薄厚度和有限的光吸收，其响应率通常较低。在这里，我们开发了一种简单且低成本的方法，通过液相剥离的 SnS 纳米片（NSs）表面修饰，制备出具有显著增强的响应率和扩展光谱响应范围的高性能单层 WS 混合光电晶体管。在 457nm 激发下，混合光电晶体管的响应率高达 2 A W，光/暗信号噪声比高达 10，与纯 WS 器件相比，响应率提高了 3 个数量级，信号噪声比提高了 100 倍。我们的混合光电探测器还表现出令人满意的响应速度，上升和下降时间分别为 51μs 和 98μs。在单层 WS 沟道顶部进行最佳的窄带隙 SnS NS 表面修饰后，也观察到了近红外区域（1064nm）的新兴光响应。
