Electronic function of organic semiconductor mediated by weak perturbation:Elucidation of misterius properties of organic device interfaces

2014 Fiscal Year Final Research Report

• Project/Area Number: 24245034
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Functional materials/Devices
• Research Institution: Chiba University
• Principal Investigator: UENO Nobuo 千葉大学, 融合科学研究科(研究院), 特任研究員 (40111413)
• Co-Investigator(Kenkyū-buntansha): KERA Satoshi 分子科学研究所, 教授 (10334202)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 有機半導体 / 有機デバイス / 界面 / エネルギー準位接合 / 電荷移動度 / 光電子分光 / 電子状態 / 電子-振動結合

Outline of Final Research Achievements

Ultrahigh-sensitivity ultraviolet photoelectron spectroscopy (UPS) was realized for radiation-sensitive organic materials and was used to investigate electronic states in band gap of organic semiconductors. The results show the striking effects for pentacene: exposure to inert gas (N2 and Ar) produces gap states and pushes the Fermi level closer to the valence band. The results demonstrate that these gap states originate from small imperfections in the molecular packing structure, which impact on the energy level alignment in various organic devices. Electronic band dispersions in insulating picene single crystals were measured by UPS coupled with laser-induced photoconductivity. Based on these fundamental studies, we fabricated C60 transistors using structure-controlled C60 thin film on DIP template/SiO2 gate insulator, and found that high electron mobility and high operational stability are achieved with the gap-states controlled C60 thin film transistors on the DIP/SiO2 gate.

Free Research Field

有機薄膜物性、有機半導体電子論