Molecular orientation and electronic properties of oriented organic thin films by means of low-energy electron transmission.

通过低能电子传输的取向有机薄膜的分子取向和电子特性。

• 批准号: 63550005
• 负责人: UENO Nobuo
• 金额: $ 1.22万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550005/
• 关键词: hot electron; oriented thin film; electron affinity; energy band; electron transmission; electron scattering; LB膜; 薄膜; 配向薄; 伝導帯; 分子デバイス; 有機分子

We investigated the correlation between the molecular orientation and the electron- transport properties for thin films of long alkyl molecules, Langmuir-Blodgett (LB) films of cadmium arachidate, LB films of polydiacetylene, evaporated films of tetratetracontane and thin films of related molecules, with low-energy electron transmission (LEET) technique. LEET spectra were measured as a function of film thickness, crystallinity, temperature and time after the film deposition.We found that (i) degree of normal molecular orientation depends on the film thickness and the orientation becomes better for the thickness larger than 4 molecular layers, (ii) a poor orientation for thinner films, 2 molecular layers, is a results of poor crystallinity, (iii) the bottom of the conduction band is located at 0.4-0.5 ev above the vacuum level and the energy position shifts to low energy side by heating due to thermal excitation of molecular vibrations, (iii) the effective efficiency of the hot- electron injection into the film is larger at low temperature, and (iv) the electron transmission through the band gap can not explained by the tunnel theory.Further, angle-resolved photoemission experiments were performed with synchrotron radiation for oriented thin films of 18-pentatriacontanone (stearone). The normal molecular orientation and energy band dispersion were observed simultaneously with this method.

利用低能电子透射（LEET）技术研究了长烷基分子薄膜、花生酸镉的Langmuir-Blodgett （LB）薄膜、聚二乙炔的LB薄膜、四四辛烷的蒸发薄膜以及相关分子薄膜的分子取向与电子输运性质的关系。测量了薄膜厚度、结晶度、温度和沉积时间对LEET光谱的影响。我们发现：(1)分子的正常取向程度取决于膜的厚度，当膜的厚度大于4个分子层时，取向更好；(2)较薄的膜（2个分子层）的取向较差，这是结晶度较差的结果；(3)导带底部位于真空水平以上0.4-0.5 ev，由于分子振动的热激发，能量位置通过加热转移到低能侧。（三）低温时热电子注入薄膜的有效效率较大；（四）电子通过带隙的传输不能用隧道理论来解释。此外，利用同步辐射对18-五元康酮（硬脂酮）取向薄膜进行了角度分辨光发射实验。该方法同时观察了正常分子取向和能带色散。

项目成果

N.Ueno et al.: "Energy band dispersion in oriented thin films of penta triacontan18-one by angle resolved photoemission with synchrotron radiation." Phys.Rev.B. 41. 1176-1183 (1990)

N.Ueno 等人：“通过同步加速器辐射的角分辨光电发射，在五十三碳一一定向薄膜中实现能带色散。”

T.Maeda et al.: "Low energy electron transmission measurements on polydiacetylene Langmuir-Blodgett films." Thin Solid Films. 179. 327-334 (1989)

T.Maeda 等人：“聚二乙炔 Langmuir-Blodgett 薄膜上的低能电子传输测量。”

N.Ueno et al.: "Mechanism of UV-and VUV-induced etching of poly(methyl-methacrylate):Evidence for an energy dependent reaction." in Polymers in Microlithography,Material and Processes,(ACS Symp.Ser.Vol.). 412. 424-436 (1989)

N.Ueno 等人：“紫外线和真空紫外线诱导聚甲基丙烯酸甲酯蚀刻的机制：能量依赖反应的证据。”

K. SUGITA and N. UENO: "Sensitivity enhancement of alpha-methylstyrene copolymer electron beam resists by force development." Polymer 30 July 1308-1313 (1989).

K. SUGITA 和 N. UENO：“α-甲基苯乙烯共聚物电子束的灵敏度增强可通过力的发展来抵抗。”

上野信雄、関和彦、藤本斉、佐藤直樹、中原弘雄、杉田和之、井口洋夫: 信学技報OME88. 88-1. 1-6 (1988)

Nobuo Ueno、Kazuhiko Seki、Hitoshi Fujimoto、Naoki Sato、Hiroo Nakahara、Kazuyuki Sugita、Hiroo Iguchi：IEICE 技术报告 OME88-1（1988）。