应变对Al_xGa_(1-x)N能带间隙弯曲系数和能带结构的影响

Effect of Strain on Band Gap Bowing and Band Structure of Al_xGa_(1-x)N

在生长AlxGa1-xN外延层过程中,由于外延层的热膨胀系数和晶格常数与衬底的不同,导致许多残留应变产生,这会影响外延层材料的能带结构和跃迁能。从理论上分析了在赝形应变下AlGaN的能带结构和弯曲系数,并通过对AlxGa1-xN能带间隙的理论结果和实验结果分析比较,得出的能带间隙的弯曲系数与已有文献报道的实验结果相吻合。

Epitaxial growth oi AlGaN on Gain has led to some amount of residual strains in the AlGaN layer due to differences between the film and substrate lattice constants and between their thermal expansion coefficients. These strains can affect the AlGaN layer＇s band structure and the transition energies. The effect of strain on band structure and bowing parameters of AlxGa1-xN which is pseudomorphically strained was analyzed theoretically. The erperimental values of the bowing parameters agree with the reported ones, and also strong dependence of the bowing parameters on composition is evaluated.