Development of Laser-Induced Material Transfer in Nanometer Regions

利用激光烧蚀和激光注入的方法，将功能性有机分子在聚合物薄膜上加工成小至450 nm的荧光特征。该技术利用压电驱动器来定位移液管，具有100 nm的孔径，并在尖端掺杂有有机分子，在聚合物膜上方数十纳米。随后使用通过光纤向下引导至尖端的半峰全宽3 ns激光脉冲照射移液管。这种烧蚀限制方法提供了精细的空间控制，用于将功能有机分子放置在指定区域中，并将在光电子学中应用。它还可以应用于药物输送或生物技术，因为在原则上，不同功能的不同分子可以以相同的方式被操纵用于不同的药物。表面改性是由于局部场蒸发后，在隧道间隙之间施加10 V。在表面改性期间和之后观察到STM针尖纳米火花下方的白色光火花。即使在施加较低电压时，将离子物质添加到另外的纯溶剂中也诱导纳米火花，但在这种情况下，没有发生表面改性。认为ITO的一部分以离子的形式溶解在溶液中，在这些诱导离子的存在下发生电子雪崩，从而为控制激光诱导的分子、电子和离子在空气/固体或液体/固体表面的转移提供了基础知识。

Functional organic molecules have been manipulated into fluorescent features as small as 450 nm on a polymer film using a method derived from laser ablation and laser implantation. The technique utilizes a piezodriver to position a pipette, having a 100 nm aperture and doped at the tip with organic molecules, tens of nanometers above a polymer film. The pipette is subsequently irradiated using 3 ns full width at half maximum laser pulses guided down to the tip by a fiber optic. This method of ablation confinement gives fine spatial control for placing functional organic molecules in a designated region and will have applications in optoelectronics. It could also be applied to drug delivery or biotechnology, because in principle, different molecules of diverse function can be manipulated in the same way for various purposes.A nanometer-scale surface modification of tin-doped indium oxide ITO in organic solvent was performed using a scanning tunneling microscope STM. The surface modification was attributed to localized field evaporation upon applying 10 V between the tunneling gap. White light sparking beneath the STM tip nanospark was observed during and after the surface modification. The addition of ionic species into the otherwise pure solvent also induced a nanospark even when applying lower voltages, but in this case, surface modification did not occur. It is considered that a part of the ITO becomes dissolved in solution as ions, which results in electron avalanche in the presence of these induced ions.Thus, fundamental knowledge was obtained for controlling laser-induced transfer of molecules, electrons, and ionic species at air/solid or liquid/solid surfaces.