Study for Electron Affinitive and emissive characteristics of Various Impurities in Silicone Oil.

本课题研究了硅油中各种杂质的亲电子性和电子发射性，即哪些杂质容易成为正离子或负离子。用薄膜隧道发射器对分馏柱蒸馏后的硅油和杂质污染后的硅油进行了电子和空穴注入，根据注入量计算了硅油中杂质的亲电子能力和电子发射能力。得到了不同杂质的电子亲合势在0 ~ 0.6eV之间，电子发射能量在2 ~ 3eV之间，发现杂质的电子亲合势和电子发射特性与杂质的结构密切相关。很明显，具有如下特殊结构的杂质具有强的电子亲和势。(1)由强酸原子如氧和铬组成的杂质。(2)电荷局部化且具有大偶极矩的杂质。(3)具有双键的大分子杂质，其<pi>电子能够相当容易地移动。当施加电场时，结构（2）和（3）的杂质似乎由于偶极的局部场而在基底和硅油之间的界面处产生降低电子发射的势垒高度的效果。换句话说，这种杂质应该具有大的电子亲和势，另一方面，结构（2）和（3）的杂质也明显具有相当大的电子发射能力。此外，具有贷款电子对的杂质具有电子发射能力。

The project was performed to investigate electron affinitive and electron emissive characters of various impurities in silicone oil, namely which kinds of impurities became easily negative or positive ions. Electron and hole were injected by a thin film tunnel emitter into two kinds of silicone oils, i.e. one was distilled by a fractionating column and another was contaminated by a dose of impurity.From the injection levels of electron and hole into such silicone oils, electron affinitive and electron emissive ability of various impurities in silicone oil were calculated. The values from 0 to 0.6 eV of electron affinity and values from 2 to 3 eV of energy for electron emission were acquired for various impurities.From the experimental results, it was found that the electron affinitive and electron emissive characters depended strongly on the structure of impurities. It became clear that such impurities having special structures as the followings had strong electron affinity.(1) Impurities made of strongly acid atoms like oxygen and chroline. (2) Impurities in which charge was localized and having large dipole moment. (3) Impurities of a large molecule with double bonds having <pi> electron which was able to move considerably easily.When electrical field is applied, the impurities of the structures (2) and (3) seem to give an effect of lowering the barrier hight for electron emission at the interface between a base and silicone oil for the sake of local field by the dipole. In other words such impurities should have large electron affinity.On the other hand it became clear that the impurities of structure (2) and (3) had a considerably large ability for electron emission also. Furthermore impurities which had loan electron pairs had an ability for electron emission.