辐照条件下典型掺杂GaN力学特性的多尺度模拟研究

Owing to the excellent ability against the radiation damage, GaN materials have been widely used in devices upon irradiation. The interaction between the radiation flux and the doped GaN materials could result in complex damage to the GaN lattices, embedded impurities, and material microstructures, which consequently damage the mechanical properties and cause the electrical and optical degradation of GaN materials, and eventually leading to low working efficiency and unstable mechanical behaviors for the GaN-based devices. Though extensive studies have been performed on the mechanical, electrical, and optical properties of GaN materials, these properties in the case of radiation damage have not been revealed. In this project, we aim to investigate the effects of radiation on the mechanical, electrical, and optical properties of impurity-doped GaN materials by building a multi-scale framework based on a combination of molecular dynamics simulations, experimental studies, and theoretical modeling. We shall investigate how the radiation damage affect the mechanical behaviors of the GaN materials across different scales and reveal the underlying physical mechanism. The proposed work may provide useful guidelines and serve as experimental data basis for the design of high-performance GaN-based devices subject to radiation damage.

由于具有良好的抗辐照损伤性能，GaN（氮化镓）作为半导体材料被大量地应用于工作在辐照环境下的电子器件中。辐照环境中的入射粒子会与GaN晶格原子、掺杂元素发生相互作用，对GaN的微结构造成损伤，进而影响其力学行为和光电性能，降低GaN器件服役寿命。尽管人们针对无辐照环境下GaN的力学和光电性能进行了大量的研究，但尚未有相关研究同时考虑辐照、应力应变对掺杂GaN材料微观结构、力学性能和光电性能的影响。本项目拟结合分子模拟、实验、理论建模，构建多尺度框架，深入研究辐照条件下掺杂GaN材料的力学行为、微观组织结构演变、光电性能的变化。考察辐照条件下不同类型掺杂GaN中缺陷、肿胀等损伤形成与演化的物理机制和规律；定量描述辐照条件下GaN材料在微观和宏观尺度上的力学行为；探究辐照和应力应变共同作用下GaN材料光电性能的调控机制。研究成果将为制备辐照条件下高可靠性的GaN器件提供理论指导和实验依据。

GaN的力学和光电性能的辐照效应研究对辐照环境下半导体器件的设计和使用具有重要意义。本项目结合实验、理论建模和分子模拟，系统研究了GaN单晶力学性能、断裂行为的辐照效应，探索了辐照作用对GaN光电性能的调控。研究结果表明GaN单晶的测量硬度随辐照剂量的增大而增加，但模量却有所降低；辐照后GaN的最大剪应力较辐照前有所增加，断裂韧性增强；辐照提高了GaN单晶的韧脆转变温度；硬度随温度升高而减小；GaN中Ga空位和N空位的存在均会使GaN的导电性能一定程度降低。项目成果发表SCI论文9篇，2篇论文在审。项目负责人在项目执行期间获得国家优秀青年基金项目支持，一位博士后研究人员出站入职高校。