弹性应变工程

Elastic Strain Engineering

弹性应变工程是指通过改变材料弹性应变的大小来调控和优化其物化性能的技术。人们早在1950年左右就发现弹性应变可以大幅提高单晶硅中载流子的迁移率,并在20世纪90年代后期将其应用在CMOS工业中,产生了数百亿美金的效益。但由于当时大弹性应变很难在其它材料体系内实现,弹性应变工程并没有引起人们的普遍关注。近年来,随着纳米材料制备技术的蓬勃发展,人们发现纳米材料能承受比其块体母材高达10～100倍的超大弹性变形。这重新燃起了人们对弹性应变工程的研究兴趣,并取得了很多富有应用前景的成果。例如,理论计算和初步的实验结果表明,拉应变能使锗从间接带隙半导体转变为直接带隙的半导体,从而显著改变其光学特性;应变梯度不仅能增加二硫化钼单分子层材料吸收太阳光的谱宽,而且能降低激子的束缚能,并使其沿应变增加方向定向移动;通过弹性应变调控可大幅提升光催化分解水制氢等。综述了弹性应变工程的发展历史和研究现状,并对其未来的发展方向进行了剖析和展望,期望为本领域的研究人员提供参考!

Elastic strain engineering(ESE)aims to utilize tensile,compressive and deviatoric shear stresses to control the physical and chemical properties of materials.It is broader than high-pressure physics,which deals with hydrostatic,compressive stress only.Since the 1950s,researchers have found that elastic strain and stress can greatly enhance the carrier mobility in semiconductors,and have utilized this in the CMOS industry since the 1990s.With the proliferation of nanomaterials that can survive large stresses(often at 10~100 times their bulk strength),ESE is receiving even more interest in recent years.For example,one may change the bandgap and even the band topology of semiconductors with stress,turning indirect-bandgap material into direct-bandgap material;one may drive exciton motion with an elastic strain gradient,which creates a bandgap gradient;one may change the surface catalytic properties with strain,etc.This article gives a brief overview of the field,and provides key references for prospective researchers.