DISPERSION OF RAMAN CROSS-SECTION IN CDS AND ZNO OVER A WIDE ENERGY RANGE
DISPERSION OF RAMAN CROSS-SECTION IN CDS AND ZNO OVER A WIDE ENERGY RANGE
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DOI：
10.1103/physrevb.7.3788
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发表时间：
1973-01-01
影响因子：
3.7
通讯作者：
CHANG, RK
中科院分区：
文献类型：
--
作者：
CALLENDER, RH;SUSSMAN, SS;CHANG, RK
用宽范围的激光能量测量了CdS和ZnO中几种声子模的拉曼散射截面的色散。本文研究了CdS中的E1（LO）模和多LO（2-LO，3-LO和4-LO）模，能量范围从0.45Eex（激子能量）到1.1Eex。对于E1（LO）模，采用了”禁止”（zz）和允许（zx）两种几何结构.在这两种几何形状中的横截面的色散行为与能量低于E ex的理论一致。本文还讨论了多LO声子散射的色散。对于ZnO，在能量范围（0。5 7-0。7 6）E ex.的LO模式的行为expalined在变形和Fröhlich之间的LO散射截面的贡献的抵消方面。对于TO模式，没有观察到共振抵消，与最近的研究结果的CdS和ZnS。一个简单的模型被用来讨论ZnO和CdS行为之间的这些差异。最后，从2-LO模式的散射在ZnO的散射光子的能量是一致的E ex的共振增强的报告。
The dispersion of the Raman cross sections of several phonon modes in CdS and ZnO using a wide range of laser energies has been measured. The E 1 (LO) and multi-LO (2-LO, 3-LO and 4-LO) modes in CdS have been studied over the energy range extending from 0.45 E ex (exciton energy) to 1.1 E ex. For the E 1 (LO) mode, both the" forbidden"•(zz) and allowed (zx) geometries were employed. The dispersive behavior of the cross section in these two geometries is in agreement with theory for energies below E ex. The dispersion of multi-LO-phonon scattering is also presented. For ZnO, the dispersion of the cross section for the E 1 (LO), E 1 (TO), A 1 (TO), and E 2 modes was measured over the energy range of (0. 5 7− 0. 7 6) E ex. The behavior of the LO modes is expalined in terms of a cancellation between the deformation and Fröhlich contributions to the LO scattering cross section. For the TO modes, resonant cancellation was not observed, in contrast to the results of recent studies of CdS and ZnS. A simple model is used to discuss these differences between the ZnO and CdS behavior. Finally, a resonant enhancement of the scattering from the 2-LO mode in ZnO when the scattered-photon energy was coincident with E ex is reported.