Synthesis and resonance Raman spectroscopy of CdS nano-wire arrays
Synthesis and resonance Raman spectroscopy of CdS nano-wire arrays
复制标题
DOI：
10.1016/0301-0104(96)00171-1
复制
发表时间：
1996-10-01
期刊：
影响因子：
2.3
通讯作者：
Moskovits, M
中科院分区：
文献类型：
--
作者：
Routkevitch, D;Haslett, TL;Moskovits, M
通过将CdS电沉积到阳极氧化铝的孔中，制备了直径在9-22 nm范围内且长度达1 μ m的高度各向异性的定向半导体纳米线阵列。半导体纳米线的激子能量的值作为线直径的函数由半导体纳米线在CdS吸收边附近的偏振共振拉曼光谱的激发波长依赖性确定，共振拉曼（RR）谱由纵向光学声子模的级数控制，级数成员的相对强度既依赖于激发波长又依赖于颗粒尺寸。LO声子频率也被发现是线直径依赖。RR光谱被发现是几乎独立的激发它们的光的偏振。光激子能量被确定为从最大直径的线的2.36 eV变化到最小直径的线的2.42 eV。不存在偏振依赖性被解释为部分地由于纳米线由半导体微晶的串组成的事实，使得微晶的局部纵横比在轴向方向上不是很大且不均匀。然而，对于最小的纳米线，径向尺寸均匀性非常高。带隙能量对纳米线直径的依赖性与理论符合得很好。
Highly anisotropic arrays of aligned semiconductor nano-wires with diameters in the range 9-22 nm and lengths up to 1 mu m were fabricated by electrodepositing CdS into the pores of anodic aluminum oxide, The value of the exciton energy of the semiconductor nano-wires was determined as a function of wire diameter from the excitation wavelength dependence of their polarized resonance Raman spectra in the vicinity of the CdS absorption edge, The resonance Raman (RR) spectra were dominated by a progression in the longitudinal optical phonon mode, The relative intensities of the members of the progression are both excitation-wavelength and particle-size dependent. The LO phonon frequency was also found to be wire-diameter dependent. The RR spectra were found to be almost independent of the polarization of the light exciting them. The optical exciton energy was determined to vary from 2.36 eV for the largest diameter wires to 2.42 eV for the smallest. The absence of polarization dependence is interpreted to be in part due to the fact that the nano-wires consist of strings of semiconductor crystallites so that the local aspect ratio of the crystallites is both not very great and not uniform in the axial direction. For the smallest nano-wires the radial size uniformity is, however, very high. The dependence of the band-gap energy on the diameter of the nano-wires is in good agreement with theory.