Electrical Characterization of Hole Transport Materials Using In-situ Field Effect Measurement

Masaaki IIZUKA  Masakazu NAKAMURA  Kazuhiro KUDO  Kuniaki TANAKA  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.6   pp.1311-1316
Publication Date: 2002/06/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Recent Progress in Organic Molecular Electronics)
Category: Fabrication and Characterization of Thin Films
hole transport materials,  TPD,  α-NPD,  m-MTDATA,  carrier mobility,  field effect measurement,  thin film transistor,  

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We investigated the electrical properties of hole transport materials such as TPD, α-NPD and m-MTDATA using in-situ field effect measurement. TPD, α-NPD and m-MTDATA films showed p-type semiconducting properties, and their electrical parameters such as conductivity, carrier mobility and carrier concentration were obtained. We also examined the effect of the substrate temperature during vacuum deposition and the thermal treatment after deposition, on the electrical parameters of the films. Experimental results showed that conductivity and carrier mobility decreased as the substrate temperature increased over the glass transition temperature. These decreases in conductivity and carrier mobility as a result of thermal treatment appear to be strongly related to the degradation mechanism of organic electroluminescent devices.