Study on the ultra low resistivity phenomenon of hetero structure organic thin films

研究了异质结构LB薄膜的制备及其电性能，以考察薄膜中的超低电阻率现象。在Hino报道的花生Cd (AA)/C_<15> TCNQ （TCNQ）的异LB膜中，从未见过超低电阻率。有人说，Z型TCNQ LB膜的自发电场和在AA/TCNQ异质界面处产生的电子云对这一现象的发生起了重要作用。此外，在本研究中，我们发现TCNQ的一部分在亚相溶液中与Cd^<2+>形成Cd-TCNQ复合物，并且该复合物可以转变为导电电荷转移（CT）复合物。假设Cd-TCNQ CT配合物在非极性AA膜和极性TCNQ LB膜的界面形成了二维导电层。这一假设暗示了金兹堡高温超导理论所依据的介电介质/二维多维导体/介电介质的异质结构可能是超低电阻率的原因。在本研究中，我们通过LB法制备了导电、极性和非极性薄膜，实现了薄膜的异质结构，并对薄膜的质量和性能进行了估计。其中，Y型花生Cd LB薄膜作为非极性薄膜具有足够的薄膜质量。在导电膜方面，利用btt - ttf （BO）和C_<15> TCNQ的CT配合物成功制备了具有足够高电导率（1- S/cm）的LB膜。对于极性薄膜，制备了交替沉积的Y型薄膜，而不是不稳定的Z型TCNQ LB薄膜。结果表明，交替沉积的薄膜具有良好的质量，7层薄膜的自发电位约为1.8 V。以上LB膜组成的非极性/导电/极性异质结构LB膜的电性能从新型分子器件的应用角度以及超低电阻率现象引起了我们的关注。少

Preparation and the electric properties of hetero structure LB films has been investigated with a view to inspect the ultra low resistivity phenomenon in the films. The ultra low resistivity has never seen in the hetero LB films of arachidic Cd (AA)/C_<15> TCNQ (TCNQ) for which Hino reported the ultra low resistivity. It has been said that the spontaneous electric field of a Z type TCNQ LB films and an electron cloud produced at the AA/TCNQ hetero interface play a important role to occur this phenomenon. Additionally, in this study, we have found that a part of TCNQ formed Cd-TCNQ complex with Cd^<2+> in a sub-phase solution and the complex could be changed to a conductive charge transfer (CT) complex. It was postulated that a two dimensional conducting layr had been formed at the interface of the non-polar AA and the polar TCNQ LB films by the Cd-TCNQ CT complex. The postulation implied us that the ultra low resistivity was probably resulted from the hetero structure of dielectric/2 d … More imensional conductor/dielectric on which the Ginzburg's theory of high temperature superconductivity based. In this study, we prepared conductive, polar and non-polar thin films by the LB method to realize the hetero structure and estimated film qualities and properties. Among these films, Y type arachidic Cd LB films has a sufficient films quality as the non-polar film. For conductive films, the LB films with a sufficiently high conductivity (1- S/cm) were successfully formed by use of a CT complex of BEDT-TTF (BO) and C_<15> TCNQ.For polar films, alternately deposited Y type films were fabricated instead of a labile Z type TCNQ LB films. It was found that the alternately deposited films have a sufficient quality and spontaneous electric potential of about 1.8 V for a 7 layrs film. The electric properties of the LB films with non-polar/conductive/polar hetero structure consisting of above LB films attract our attention from the application view point of new molecular devices as well as the ultra low resistivity phenomenon. Less