EVALUATION OF MOLECULAR ORGANIC MONOLAYER BY SPACIAL RESOLVED INELASTIC ELECTRON TUNNELING SPECTROSCOPY

为了获得基于STM针尖的IETS测量系统的高密度记录系统的基本信息，我们通过施加电压脉冲研究了Langmuir-Blodgett （LB）薄膜的IETS变化。实验采用欧米茄-三醇酸（omegaT）和二乙炔单体（DA） LB膜。这些薄膜的化学反应可以通过电压脉冲预测，因为omegaT和DA分别可以通过电子束和紫外线照射聚合。主要结果总结如下。1)在施加电压脉冲的作用下，大多数IETS峰呈现幅值变化和峰移。2) IETS和FT-IR-RAS的变化表明，IETS的变化局限于隧道电流集中的局部区域。3) omegaT LB膜的IETS变化是由电压脉冲引起的聚合等化学反应引起的。4)施加-20 V的负电压脉冲，可以可逆地改变正电压脉冲诱导的DA LB膜let变化。这个结果对于可重写存储系统是有吸引力的。

Inorder to obtain the basic information for high-density recording system based on IETS measurement system equiped with STM tip, we have investigated the change of IETS of Langmuir-Blodgett (LB) films by applying a voltage pulse. In the experiment, LB films of omega-tricosenoic acid (omegaT) and diacetylene monomer (DA) were employed. The chemical reactions of these films are expected by the voltage pulse because omegaT and DA can be polymerized by electron beam and UV light exposure, respectively. Main results are summarized below.1) Most of IETS peaks show amplitude changes and peak shifts by applying voltage pulse.2) The changes in IETS and FT-IR-RAS indicate that the change obserbed in IETS is restricted in local area where the tunneling current concentrates.3) The changes of IETS of omegaT LB films are due to the polymerization and other chemical reactions induced by the voltage pulse.4) The LETS change induced by the positive voltage pulse in DA LB films was modified reversibly by applying negative voltage pulse of -20 V.This result is attractive for a rewritable memory system.