双轴应变对纤锌矿GaN、AlN、InN及其合金电子有效质量的影响(英文)

利用第一性原理计算方法密度泛函理论的局域密度近似计算了纤锌矿氮化铝(AlN)、氮化镓(GaN)、氮化铟(InN)及其合金在双轴应变下的电子有效质量。对于GaN和AlN,张应变使电子有效质量增大而压应变使电子有效质量减少,但却使InN电子有效质量在张应变和压应变下都增大。由于三元合金(AlxGa1-xN,InxGa1-xN和AlxIn1-xN)与GaN异质结的新颖特性,同时计算了三元合金在松弛和应变下电子有效质量的变化趋势。受制于GaN基板的平面应力,外延AlxGa1-xN和AlxIn1-xN电子有效质量将减少,而InxGa1-xN电子有效质量增大,且随着In含量变大而更显著。对铟氮化合物应变下电子有效质量异常的机制也做了讨论。

Effects of Biaxial Strain on Electron Effective Mass of Wurtzite AlN, GaN, InN and Their Ternary Alloys

The electron effective mass for relaxed and in-plane biaxial strained wurtzite AlN,GaN,InN and their ternary alloys(AlxGa1-xN,InxGa1-xN and AlxIn1-xN) was calculated using the density functional theory with local density approximation.The tensile strain increases the electron effective mass and the compressive strain has an opposite effect on GaN and AlN,while the InN is an exception that the effective mass increases under both tensile and compressive strain.Compared with the relaxed alloys,the electron effective mass of alloys strained with coherent epitaxial GaN substrate decreases with the increase of lattice match for AlxGa1-xN and AlxIn1-xN.However,for InxGa1-xN,the strain increases the electron effective mass,especially for large In mole fraction due to the large compressive strain.The unusual mechanism of the effective mass for In Nitride is also discussed.