氮化硼纳米材料的结构及电学特性研究

Boron nitride (BN) nanomaterials have similar structure to carbon nanomaterials, but they also possess properties unavailable in their counterparts, for example, BN nanomaterials are potential candidates for building nano electro-device because of tunable electrical properties and anti-oxidation in high temperature. However, the preparation of BN nanomaterials is facing to poor purity and low yield, which prevents their large scale use. In this research, we systematic study into low-dimensional BN nanomaterial through quantum size effect model, structure synthesis, bandgap modulation as well as interface contact properties. In the part of theoretical research, the quantum size effect model will be built by first principle. The structure of BN will be investigated in atom scale to analyze related quantum effects, which as the foundation of synthesis and modulation of BN structure. The synthesis of regular stratified BN nanoribbons is quite challenging, here we introduce an improved ball milling and annealing method for the large-scale production of low-dimensional BN nanostructure with high purity and unique edge states. Based on the model and structure synthesis research, the gandgap modulation of BN will be achieved by micro electronical and MEMS technique. The results will be discussed to explain the modulation mechanism as well as to validate quantum effect model. Further, the investigation of electrical contact interface of BN nanostructure is necessary. The electrical test system will be built to test the contact property of BN structure in device. Above the results, evaluation systems of electrical contact of BN interface will be discussed for the first time. Through the discussion on BN nanomaterials, we realize that low dimension BN structure are promising materials on filed effect transistors and other nanoelectric devices. The investigation is highly significant to promote applications of BN nanomaterials.

氮化硼（BN）纳米材料以高热稳定性和电学可调谐性弥补了碳纳米材料的不足，成为纳电材料研究新热点。然而，对BN结构制备和特性等问题的基础研究仍处于起步阶段，阻碍了材料在电子器件实用化方面的研究。本课题围绕量子尺寸模型、纳米结构加工、带宽调制、界面电接触等问题对BN纳米材料展开系统的研究。课题首先通过第一原理建立量子尺寸效应模型，从原子层面剖析BN纳米结构，分析相关量子效应，指导低维结构合成和带宽调制；通过辅助球磨新技术合成类石墨烯低维BN纳米结构，解决尺寸不均一、边缘缺陷多等不适于器件加工的实际问题。在此基础上，结合微电子和MEMS技术，实现BN结构的带宽调制，探索调制机理，验证量子模型。进一步，针对电子组件时的电接触问题，完成本征结构与掺杂结构的界面接触测试，首次建立BN材料电接触评价体系。该课题的研究为BN纳米结构在电子器件中的实用化奠定了基础。

氮化硼（BN）纳米材料以高热稳定性和电学可调谐性弥补了碳纳米材料的不足，本项目围绕量子尺寸模型、纳米结构加工、带宽调制、界面电接触等问题对BN纳米材料展开了系统的研究。首先，我们通过第一性原理和密度泛函理论建立了纳米管一维材料的量子尺寸模型，从原子层面剖析BN的纳米结构，通过计算得到费米能级、能带结构、态密度等电学特性参数，完成了不同元素掺杂的自旋极化纳米体系的电学特性研究。具体分析了IV、VI族元素硅、碳、硫、氧、钛等掺杂后的相关量子效应，从理论层面指导了低维掺杂结构的合成，预测了不同掺杂元素对纳米结构的带宽调制效应以及相关的自旋效应。制备方面，通过催化辅助球磨的新技术，合成了竹节结构和圆柱结构的氮化硼纳米管；采用原位合成手段初步合成了类石墨烯的BN纳米带结构，从制备方法改进和高效催化剂两方面完成了BN纳米材料的催化生长机理研究，并且解决了BN二维纳米片结构固有生长方法中合成尺寸不均一、边缘缺陷多等问题，更有利于今后纳电器件的加工和应用。采用掺杂的方法对BN纳米材料进行了带宽调控研究。实验结果显示，硅、碳、硫掺杂结构相对稳定，与硅元素相比较，硫、碳掺杂的能带调控优势明显。氧元素由于自掺杂效应，少量存在于BN纳米结构中，当人为控制氧元素掺杂含量时，可发生明显的带宽调制。在此基础上，结合微电子和MEMS技术，实现BN纳米结构的带宽调制测试，验证了尺寸模型的正确性。针对电子组件时的电接触问题进行了电极的优化设计、合金以及后处理工艺，完成了本征结构与掺杂结构的界面接触测试。项目形成了材料制备、掺杂工艺、电极优化设计到带宽调控的氮化硼纳米材料界面接触评价体系，为BN纳米结构在电子器件中的实用化奠定了基础。