Exploration of ballistic conduction on the femtosecond scale in organic semiconductors

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13334
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Applied materials
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Unuma Takeya 長岡技術科学大学, 工学研究科, 准教授 (20456693)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 共役ポリマー / テラヘルツ放射 / フェムト秒 / 超高速現象 / 高電場効果

Outline of Final Research Achievements

We investigated the ultrafast motion of electrons and holes under bias electric field in conjugated polymers, which are major organic semiconductors, on the basis of emitted terahertz waveforms. When several conjugated polymer films with different main chains were excited by femtosecond laser pulses, the obtained terahertz signals were found to have the same order of magnitude and quite similar shapes. This means that the ultrafast motion is common to the conjugated polymers. A detailed analysis of terahertz waveforms revealed that the polarization relevant to terahertz emission is created by electron-hole pairs and quenched on the time scale of less than 350 fs.

Free Research Field

半導体物性