Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721 302, India.
Nanoscale. 2016 Oct 27;8(42):18143-18149. doi: 10.1039/c6nr06841c.
Herein, we report the graded electronic band gap along the axis of individual heterostructured WZ-ZB InAs/InSbAs nanowires. Resonance Raman imaging has been exploited to map the axial variation in the second excitation gap energy (E) at the high symmetry point (L point) of the Brillouin zone. We relate the origin of the observed evolution of the gap energy to the fine tuning of the alloy composition from the tip towards the interface of the nanowire. The electronic band structures of InAs, InSb and InSbAs alloy systems at x = 0.125, 0.25, 0.50, 0.75 and 0.875, using the all electron density functional theory code Wien2k, are reported. The measured band gap along the axis of the InAs/InSbAs nanowire is correlated with the calculated gap energy at the A point and the L point of the Brillouin zone for InAs and InSbAs, respectively. We draw a one-to-one correspondence between the variation of the E gap and the fundamental E gap in the calculated electronic band structure and propose the graded fundamental gap energy across the axis of the nanowire.
在此，我们报告了沿单个异质结构 WZ-ZB InAs/InSbAs 纳米线轴向的分级能带隙。我们利用共振拉曼成像技术来绘制布里渊区高对称点 (L 点) 处第二激发能隙(E)的轴向变化。我们将观察到的能隙能量的演变归因于从纳米线尖端到界面处的合金成分的精细调整。利用全电子密度泛函理论代码 Wien2k，报道了 InAs、InSb 和 InSbAs 合金系统在 x = 0.125、0.25、0.50、0.75 和 0.875 时的能带结构。测量的 InAs/InSbAs 纳米线沿轴向的能带隙与布里渊区 A 点和 L 点的计算能带隙能量分别与 InAs 和 InSbAs 相关。我们在 E 能隙的变化和计算电子能带结构中的基本 E 能隙之间建立了一一对应关系，并提出了在纳米线轴向上的分级基本能隙能量。
