ZnO/CdS/Cu2ZnSnS4 芯-双鞘纳米棒阵列电子输运特性研究

ZnO based core/double-shell nanorods have attracted considerable attention due to its outstanding optoelectronic and electronic properties. One of research focus is how to modulate electronic structure and transports of ZnO based core/double-shell nanorods. In this proposal, ZnO, CdS, and Cu2ZnSnS4(CZTS) are selected as subjects. ZnO/CdS/CZTS core/double shell nanorod arrays free-standing on silicon (or glass) substrates controllably are synthesized via a Successive Ionic Layer Adsorption and Reaction method. The formation mechanism of ZnO/CdS/CZTS heterostructure is revaled by varying growth condition and polarity attachment. The relationship among various grwoth condition, the change of radius of core/the thickness of shell and the distribution of carrier are investigated by the measurement of electrical charactrization in order to achieve the depedenece relationship among carrier transport and electrode materials, light irraditation and temperature. Compared with theory simulation, controlable transport mechanism and the effect of double shell on the electronic transport of heterostructure nanorods are revealed. This will lay the foundation for the application on micro/nano devices. Fabrication, electronic transport and photovoltaic properties of ZnO/CdS/CZTS core/double-shell nanorod arrays on grapheme is explored and in order to disclose the role of grapheme on improving the optoelectronic performance of ZnO/CdS/CZTS core/double-shell nanorod arrays. This proposal might provide basis for applying ZnO/CdS/CZTS core/double-shell nanorod arrays to fabricating novel mico/nano-scale optoelectronic, electronic devices etc.

ZnO基芯-双鞘纳米棒优良的光电子性能吸引了国内外研究的广泛关注，调控其电子结构和输运特性是研究的焦点之一。本项目以ZnO、CdS和Cu2ZnSnS4(CZTS)为研究对象，利用连续离子层吸附与反应法在硅衬底上实现ZnO/CdS/CZTS芯-双鞘纳米棒阵列的可控制备，通过变化生长条件和极性吸附揭示异质结形成机理。通过电学性质测量，弄清在不同生长条件下，芯径、鞘厚度变化与载流子分布的关系，获得载流子输运与电极材料、光照、温度的依赖关系；通过理论模拟比较，最终揭示双鞘对芯-双鞘纳米棒电子输运性质的影响以及可控的输运机理，为其在微纳米器件的应用奠定基础。尝试在石墨烯上生长ZnO/CdS/CZTS 芯-双鞘纳米棒阵列，通过对电子输运特性以及光伏效应的研究，揭示石墨烯对提高芯-双鞘纳米棒阵列光电转换性能的作用。本项目研究结果将为ZnO/CdS/CZTS纳米棒阵列应用于构筑新型微纳光电子器件提供依据。

本项目发展了溶液路线，以ZnO纳米棒为模板，实现了ZnO/CdS/Cu2ZnSnS4异质结纳米棒的可控制备，ZnO/CdS/Cu2ZnSnS4异质结纳米棒本身是一个pn结；在弄清其生长机理的基础上制备出ZnO/CdS/MoS2纳米棒阵列，并探索制备ZnO/CdS/Cu2ZnSnS2/MoS2纳米棒阵列；发展了旋涂法，首次制备出p型Cu2ZnSnS4纳米棒，在此基础上利用两步旋涂法形成Cu2Zn1-xCdxS4固溶纳米棒，该纳米棒可以调节Cu2ZnSnS4的带隙，另外Cu2Zn1-xCdxS4的声子谱也受到Cd成分的调制，本固溶体和Cu2ZnSnS4相比具有良好的光电响应特性。系统研究了ZnO/CdS/Cu2ZnSnS4异质结纳米棒、Cu2ZnSnS4纳米颗粒和薄膜的声子动力学特性，Cu2ZnSnS4中声子特性会受到形貌、尺寸和表面态的调制。发展了水热法，成功制备出少层MoS2纳米片，利用零维SnO2、一维TiO2、VO2对MoS2进行修饰，形成MoS2基复合材料, 并系统研究了这类材料的电化学特性。发现通过零维、一维材料的修饰，MoS2基复合材料表现出优势的电化学特性，这为二维材料MoS2修饰ZnO/CdS/Cu2ZnSnS4提供实验基础。同时发展一步热蒸发实现了p型CdS纳米带的制备，选择Sn作为掺杂剂，解决了II-VI中p型掺杂难实现的问题，进而为实现稳定p型ZnO奠定基础。构筑了Fe:TiO2 / n-Si异质结、大面积二维PbI2 和ZnO/CdS/Cu2ZnSnS4异质结纳米棒光探测器并系统研究其性能。特别是Fe:TiO2 / n-Si异质结紫外-可见光探测器具有如下优异性能：（i）异质结光电探测器在自供电模式工作中表现出超灵敏（开/关比率高达1000），快速（上升/衰减时间<10 / 15 ms）和宽光谱（紫外-可见）的光电探测性质；（ii）在零偏压0.5 mW∙cm-2的光强下，器件表现出高达46 mA / W（350 nm）和60 mA / W（600 nm）的高响应度（iii）基于内建电场下耗尽区中分离的光生电子-空穴对，讨论了器件优良光响应的物理机制。部分研究成果在Appl.Phys. Lett., J. Phys. D, J. Appl. Phys.,等国际重要学术刊物上发表16篇论文，授权3项发明专利。