采用水平滑移石墨舟液相外延生长技术在n型(100)InAs衬底上生长了InAs0.96Sb0.04薄膜.在1.5~5.5eV光子能量范围采用紫外-可见光椭圆偏振光谱仪于室温下测试了其介电函数谱ε(E).基于电子带间跃迁和联合态密度理论,采用S.Adachi的MDF模型对s(E)进行了拟合,并计算了各种临界点电子跃迁对ε(E)的贡献,结果表明:实验数据与模型吻合得非常好,E1和E1+△1跃迁发生在布里渊区(BZ)的∧轴或L点,分别对应于M1型临界点∧5^v→∧6^c(或L4.5→L6^c)和∧6^v→∧6^c(或L6^v→L6^c)跃迁;E2跃迁是由于M2型和M2型鞍点能量简并引起的,沿着BZ的∑和△轴方向.
InAs0.96Sb0.04 infrared thin films were grown by liquid phase epitaxy on n-type (100) InAs substrate by using horizontally sliding multi-wells graphite boats. The dielectric function e(E) was measured by using spectroscopic ellipsometry at room temperature within 1.5-5.5 eV. Based on the theory of the electronic interband transition and jonit state denisty, the ε(E) spectra were analyzed by S. Adachi' s MDF model and the individual contribution from each critical point (CP) was also calculated. The results show that excellent agreement between the model calculation and the experimental data is achieved over the entire energy range studied. E1 and E1 +△1 transitions are assigned to M1-type ∧5^v→∧6^c (or L4.5^v→L6^c ) and ∧6^v→∧6^c ( or L6^v→L6^c ), respectively, which are along the A symmetry axis ( or near the L point) in the first Brillouin zone (BZ). E2 transition, which is due to the degenerate of M1-type and M2-type CPs, is expected to take place along ∑ or △ axis.