Investigation of the Electrostatic Phenomena at Pentacene/Metal Interface by Second-Harmonic Generation
Investigation of the Electrostatic Phenomena at Pentacene/Metal Interface by Second-Harmonic Generation
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DOI：
10.1143/jjap.44.2818
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发表时间：
2005-04
影响因子：
1.5
通讯作者：
T. Manaka;Yuuma Suzue;M. Iwamoto
中科院分区：
文献类型：
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作者：
T. Manaka;Yuuma Suzue;M. Iwamoto
基于界面处发生的静电现象，研究了沉积在铝 (Al) 表面上的真空蒸发并五苯薄膜中的光学二次谐波产生 (SHG)。中心对称分子中的 SH 过程是由静电场（即表面电势）激活的。由于电场感应二次谐波被归类为三阶非线性光学过程，因此其谐振条件与源自电四极杆的谐振条件不同。在并五苯/Al结构的SHG光谱中，在约560 nm和660 nm处观察到两个突出的峰，而在并五苯/玻璃结构中仅在约560 nm处观察到一个峰。这些结果是基于由于电子从金属到并五苯的位移而在沉积在 Al 上的并五苯层中形成的表面电势进行讨论的。研究了光照射对二次谐波光谱的影响，以证实电场诱导二次谐波的存在。
Optical second-harmonic generation (SHG) in a vacuum evaporated pentacene thin film deposited on an aluminum (Al) surface was investigated on the basis of the electrostatic phenomena occurring at the interface. The SH process in centrosymmetric molecules is activated by the static electric field, i.e., the surface potential. Since electric field-induced SHG is classified as a third-order nonlinear optical process, its resonant condition differs from the one originating in the electric quadrupole. In the SHG spectrum of the pentacene/Al structure, two prominent peaks were observed at approximately 560 nm and 660 nm, whereas only one peak located at approximately 560 nm was observed in pentacene/glass structure. These results are discussed on the basis of the surface potential formed in the pentacene layer deposited on Al due to the displacement of electrons from metal to pentacene. The effects of photoirradiation on the SH spectrum were investigated to confirm the presence of the electric field-induced SHG.