高纵横比单层MoS_(2)纳米-微米带的可控合成及其在高性能光电晶体管中的应用

Controllable synthesis of high-aspect-ratio monolayer MoS_(2) nanomicroribbons for high-performance phototransistors

本文报道了一种快速、可控合成单层MoS_(2)纳米-微米带的方法:通过在蓝宝石衬底上旋涂Na_(2)MoO_(4)和NaOH的混合溶液后一步化学气相沉积硫化的方式进行生长.其中,通过改变NaOH的浓度,对气-液-固生长过程中的反应物液滴流动性进行调控,我们实现了对所获得的MoS_(2)的形貌和取向的调控;同时,通过改变生长时间,可以实现对MoS_(2)层数的调控.利用这种方法,我们获得了最窄宽度仅为200 nm,纵横比超过100的单层MoS_(2)纳米-微米带,且表征证明其具有很高的晶体质量.同时,我们还用该MoS_(2)纳米带作为沟道材料,制备了光电晶体管,测试表明其具有高达9×10^(5)的电流开/关比、超过10^(5)的光暗电流比以及高达8.6 A W^(-1)的响应度,展现了其在电子和光电子器件中的应用潜力.

Low-dimensional molybdenum disulfide(MoS_(2))is a versatile platform for ultrathin electronic,optoelectronic,and quantum devices,owing to the unique properties emerged in the reduced dimensionality.However,it remains challenging to develop facile synthesis methods for explicit control of their morphology and dimensionality.Herein,a simple and cost-effective method is developed for fast and controllable synthesis of monolayer MoS_(2) nano-microribbons.A mixed aqueous solution of Na_(2)MoO_(4) and NaOH was spin-coated on a sapphire substrate and sulfurated via a one-step chemical vapor deposition.NaOH concentration can control the morphology and orientation distribution of MoS_(2),while the growth time can control the thickness of MoS_(2).Notably,highquality monolayer MoS_(2) nano-microribbons with aspect ratios over 100 and widths as narrow as 200 nm were successfully synthesized,as confirmed by optical microscopy,scanning electron microscopy,atomic force microscopy,and Raman and photoluminescence spectroscopies.In addition,a phototransistor was fabricated based on the monolayer MoS_(2) nanomicroribbons,demonstrating an excellent current on/off ratio of 9×10^(5),a high photo-to-dark current ratio of 10^(5),and a strong responsivity of 8.6 A W^(−1).Therefore,this work presents an alternative pathway for the synthesis of high-aspectratio MoS_(2) ribbons,which could inspire their applications for ultrathin electronic and optoelectronic devices.