尺寸、温度、压强及其耦合对低维半导体的弹性和带隙的影响

Low dimensional semiconductors exhibit novel photoelectric and mechanical properties with the changes of their size, shape, external temperature, and pressure. These novel properties bring the opportunity for new technology and industrial revolution, and also the challenge for scientific research. Studying the intrinsic relation and control factors of these novel photoelectric and mechanical behaviors is the necessity due to the development of the material science and condensed matter physics, and also the one of the hot topics. From the formation, break, relaxation, and vibration of the bonds of low dimensional GaN, SiC, and AlN and their corresponding quantum pinning, polarization, localization, densification of skin-depth energy and electrons, we plan to research the key factors,intrinsic mechanism,and intrinsic relation of changes of their elastic and band gap with the changes of size, temperature, pressure and their coupling base on developing the bond-order-length-strength (BOLS) correlation mechanism and the local bond average (LBA) approach and research experience on ZnO (< Chemical Review >, 2012). These works will develop and perfect our BOLS correlation mechanism system, and provide a theoretical basis for researching elasticity and band gap, and designing and assembling device of low dimensional semiconductors.

低维半导体材料在它们的尺寸和形状以及外界温度、压强变化时显示出反常的光电力学性能，这些新奇的性能为新的技术和产业革命发展带来了契机，同时也对科学研究带来了挑战。研究这些新奇的光电力学性能的内在关联和控制因素是材料科学和凝聚态物理发展的必然，也是目前研究热点之一。本项目拟以低维GaN、SiC和AlN为研究对象，基于我们近期发展的键弛豫理论和局域键平均近似方法以及对ZnO的研究经验(<Chemical Review>，2012)，从材料的化学键的形成，断裂，振动和弛豫以及相应的能量和电子的量子钉扎、极化、局域化和致密化角度出发，从理论上探讨尺寸、温度、压强及其耦合引发它们的弹性和带隙变化的关键因素、内在物理机制以及变化规律的内在联系,发展和完善我们的键驰豫理论系统，从而为低维半导体的弹性和带隙的研究及器件的设计和组装提供理论基础。

弹性和带隙是纳米半导体的重要物理性能。纳米半导体的弹性和带隙随样品尺寸和形状及外界温度、压力等的变化规律一直是物理学和固体力学领域难以解决的课题之一。在纳米尺度范围内，微观的量子力学和分子动力学以及宏观的连续介质力学均遇到了不同程度的困难和阻力。因此发展新的理论方法用于解释和预测低维半导体的弹性和带隙具有非常重要的意义。在本项目的资助下，项目申请人及项目成员致力于发展和完善键弛豫理论和局域键平均近似方法， 建立了半导体的弹性模量和禁带宽度与尺寸、形状、温度及压强的解析函数关系；从化学键的形成、断裂、弛豫和振动的角度出发，寻求反映物理本质的解析解，建立‘纳米半导体的弹性和带隙-键弛豫’的相关理论框架，从而预测尺寸和形状以及外界温度、压力对纳米半导体的弹性和带隙的影响。目前已经完成的工作基本涵盖项目预定目标。研究结果一定程度上能为纳米半导体的弹性和带隙的研究及半导体材料的应用提供理论依据。在本项目资金资助下，研究成果已经以学术论文的形式在 J. Appl. Phys., Appl. Phys. Lett., Current Nanoscience， Nano 等杂志上发表了4篇，已投稿件1篇，撰写中论文1篇，资助培养研究生5名。