Bi2O2Se纳米带的气-液-固生长与高性能晶体管的构筑

Vapor-Liquid-Solid Growth of Bi2O2Se Nanoribbons for High-Performance Transistors

作为一种具有高迁移率、高空气稳定性和带隙可调的二维材料,纳米硒氧化铋(Bi2O2Se)半导体有望成为未来电子学集成器件和光电子集成器件沟道材料的候选半导体。高质量的Bi2O2Se纳米带有望用于高性能晶体管的构筑;然而,其一维结构的合成方法尚未开发。在我们的研究中,我们在云母衬底上通过Bi催化汽-液-固生长机制合成了一维Bi2O2Se纳米带。合成的Bi2O2Se单晶纳米带的宽度为100 nm到20μm,长度可达亚毫米。再者,Bi2O2Se纳米带可以很容易地利用洁净转移方法被转移到Si O2/Si衬底上,并进一步制备成高性能场效应器件。Bi2O2Se纳米带场效应器件表现出优异的电学性质:室温电子迁移率高达~220 cm2·V-1·s-1,开关比高达>106,10μm沟道长度下电流密度高达~42μA·μm-1。由此说明,Bi2O2Se纳米带有望成为候选材料用于未来高性能晶体管的构筑。

Nanostructured bismuth oxyselenide(Bi2 O2 Se)semiconductor,a two-dimensional(2 D)materials with highmobility,air-stability,and tunable bandgap,has recently emerged as a candidate of channel material for future digital(electronic and optoelectronic)applications.In terms of material morphology,some basic issues will be addressed when a twodimensional layered crystal is shaped into a one-dimensional(1 D)geometry due to size effect;these include the spaceconfined transport in a plane,which leads to dramatic changes in electronic,optical,and thermal properties.These novel 1 D nanostructures with unique properties are an optimal choice for fabricating next-generation integrated circuits and functional devices within the nanometer scale such as gate-all-around field-effect transistors,single-electron transistors,chemical sensors,and THz detectors.As one of the high-mobility 2 D semiconductor,1 D high-quality Bi2O2 Se nanoribbons could be promising for applications in high-performance transistors;however,their synthesis has not been completely developed yet.In our study,we report on the facile growth of Bi2O2 Se nanoribbons on mica substrates via a bismuthcatalyzed vapor-liquid-solid(VLS)mechanism.The preparation of Bi2O2 Se nanoribbons is based on a previous work that emphasized on the oxidation of Bi2 Se3 in a chemical vapor deposition(CVD)system and the use of bismuth(Bi)particles as the precursor of Bi catalysis.The morphology,composition,and structure of the as-grown Bi2O2 Se nanoribbons were characterized by scanning electron microscopy(SEM),atomic force microscopy(AFM),Raman spectroscopy,transmission electron microscopy(TEM),as well as other methods.For a Bi mediated VLS growth process,the growth of Bi2O2 Se nanoribbons can be self-assembled;further,in this process,as-grown epitaxial Bi2O2 Se nanoribbons are free-standing with out-of-plane morphology on the mica substrate.Additionally,combining the spherical aberration corrected transmission electron microscope(ACTEM)and selected electron diffraction(SAED)methods,we discovered that the assynthesized Bi2O2 Se nanoribbons were single crystalline with high quality.We further investigated the controllable growth for domain size by optimizing the growth temperature of the Bi2O2 Se nanoribbons.As-synthesized single-crystal Bi2O2 Se nanoribbons have widths in the range of 100 nm to 20μm and lengths in the sub-millimeter range.By employing a polymer poly(methyl methacrylate)(PMMA)assisted clean transfer method with the assistance of deionized water,the Bi2O2 Se nanoribbons can be easily transferred onto a Si O2/Si substrate.Fabricated into the top-gated field-effect device,the Bi2O2 Se nanoribbon sample(transferred to the Si O2/Si substrate)exhibited high electronic performances;these included a high electron mobility of 220 cm2·V-1·s-1 at room temperature,good switching behavior with on/off ratio of>106,and high on current density of 42μA·μm-1 at a channel length of 10μm.Therefore,Bi2O2 Se nanoribbons are expected to be a promising materials for building high-performance transistors in the future.