The wavelength dependence of photoinduced hot electron dissociative attachment to methyl bromide adsorbed on gallium arsenide (110)
The wavelength dependence of photoinduced hot electron dissociative attachment to methyl bromide adsorbed on gallium arsenide (110)
复制标题
光致热电子解离附着在砷化镓上的甲基溴的波长依赖性 (110)
DOI：
10.1063/1.476970
复制
发表时间：
1998
影响因子：
4.4
通讯作者：
R. Osgood
中科院分区：
文献类型：
--
作者：
N. Camillone;K. A. Khan;P. J. Lasky;L. Wu;J. Moryl;R. Osgood
本文测量了CH_3Br在GaAs（110）表面单分子层上通过热电子的解离电子附着（DEA）光诱导解离的波长依赖性。当入射波长从308 nm变化到550 nm时，解离截面单调减小两个数量级。有一个明显的阈值附近490 nm（2.5 eV），远低于气相光解离阈值附近250 nm（5.0 eV），但在良好的协议与一个简单的估计的基础上的预期值的光致发射阈值的降低和降低的分子亲和力水平吸附在半导体表面上的CH3Br。所观察到的阈值被发现移动到更高的能量作为单分子层的解离进行。基于Hasselbrink及其同事的工作[F. Weik，A. de Meijere和E. Hasselbrink，J.Chem.Phys.99，682（1993）]，提出了一个简单的理论模型，该模型考虑了热电子通过界面的隧穿。
The wavelength dependence of photoinduced dissociation of CH3Br via dissociative electron attachment (DEA) of “hot” electrons for one monolayer CH3Br adsorbed on GaAs(110) has been measured. The cross section for dissociation is found to decrease monotonically by two orders of magnitude as the incident wavelength is varied from 308 to 550 nm. There is an apparent threshold near 490 nm (2.5 eV), well below the gas phase photodissociation threshold near 250 nm (5.0 eV), but in good agreement with a simple estimate based on expected values for the decrease in the photoemission threshold and the lowering of the molecular affinity level upon adsorption of CH3Br on a semiconductor surface. The observed threshold is found to move to higher energy as dissociation of the monolayer proceeds. Based on the work of Hasselbrink and co-workers [F. Weik, A. de Meijere, and E. Hasselbrink, J. Chem. Phys. 99, 682 (1993)], a simple theoretical model is developed which considers the tunneling of hot electrons through the int...