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Improved charge carrier mobility in copper phthalocyanine based field effect transistors by insertion of a thin poorly conducting layer as gate insulator extension
Author(s) -
Jastrombek Diana,
Tavares Ana C. B.,
Meruvia Michelle S.,
Koehler Marlus,
Hümmelgen Ivo A.
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532278
Subject(s) - materials science , optoelectronics , transconductance , transistor , induced high electron mobility transistor , electron mobility , insulator (electricity) , thin film transistor , field effect transistor , charge carrier , semiconductor , threshold voltage , nanotechnology , electrical engineering , voltage , layer (electronics) , engineering
The charge carrier mobility is an important parameter that directly affects the performance of organic field‐effect transistors. We use copper phthalocyanine (CuPc)‐based transistors having crosslinked poly(vinyl alcohol) (cr‐PVA) as gate insulator to study the variation of the mobility in CuPc with the distance from the gate insulator interface. By measuring the mobility of the charge carriers flowing along the channel as a function of the minimum thickness of the effective channel near to the transistor source, we demonstrate that the mobility is low near to the interface and shows a maximum at approximately 5 nm from the interface. The mobility dependence on distance from interface can be modified through the inclusion of a poorly conducting thin PEDOT:PSS layer between gate insulator and channel semiconductor, which effectively acts as a gate insulator extension. This procedure is a simple but efficient strategy to improve organic field‐effect transistor performance, positively affecting the transconductance and the mobility, which in the studied devices is increased by a factor 20. The improvement is attributed to the suppression of the deleterious consequences of interface charge traps on transport along the channel and is, in principle, a general approach applicable to other organic field‐effect transistor materials combinations.