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Extracting Parameters from the Current–Voltage Characteristics of Organic Field‐Effect Transistors
Author(s) -
Horowitz G.,
Lang P.,
Mottaghi M.,
Aubin H.
Publication year - 2004
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200305122
Subject(s) - materials science , pentacene , transconductance , threshold voltage , field effect transistor , optoelectronics , gate oxide , negative bias temperature instability , voltage , electron mobility , transistor , drain induced barrier lowering , oxide , analytical chemistry (journal) , thin film transistor , nanotechnology , layer (electronics) , electrical engineering , chemistry , engineering , chromatography , metallurgy
Organic field‐effect transistors were fabricated with vapor‐deposited pentacene on aluminum oxide insulating layers. Several methods are used in order to extract the mobility and threshold voltage from the transfer characteristic of the devices. In all cases, the mobility is found to depend on the gate voltage. The first method consists of deriving the drain current as a function of gate voltage (transconductance), leading to the so‐called field‐effect mobility. In the second method, we assume a power‐law dependence of the mobility with gate voltage together with a constant contact resistance. The third method is the so‐called transfer line method, in which several devices with various channel length are used. It is shown that the mobility is significantly enhanced by modifying the aluminum oxide layer with carboxylic acid self‐assembled monolayers prior to pentacene deposition. The methods used to extract parameters yield threshold voltages with an absolute value of less than 2 V. It is also shown that there is a shift of the threshold voltage after modification of the aluminum oxide layer. These features seem to confirm the validity of the parameter‐extraction methods.