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

Research Project

Project/Area Number	05452182
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	Electronic materials/Electric materials
Research Institution	Tohoku University
Principal Investigator	YAMASHITA Tsutomu Tohoku Univversity Professor, 電気通信研究所, 教授 (30006259)
Co-Investigator(Kenkyū-buntansha)	OSHIMA Shigetoshi Yamagata Univversity Professor, 工学部, 教授 (40124557) NAKAJIMA Kensuke Tohoku Univversity Associate Professor, 電気通信研究所, 助教授 (70198084)
Project Period (FY)	1993 – 1994
Project Status	Completed (Fiscal Year 1994)
Budget Amount *help	¥7,000,000 (Direct Cost: ¥7,000,000) Fiscal Year 1994: ¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1993: ¥5,000,000 (Direct Cost: ¥5,000,000)
Keywords	LB films / Ultra low resistivity / Organic superconductor / Conductive organic thin films / 有機単分子膜 / ヘテロ構造 / TCNQ / アラキジン酸カドミウム / ステアリル・アミン
Research Abstract	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