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Current‐Induced Joule Heating and Electrical Field Effects in Low Temperature Measurements on TIPS Pentacene Thin Film Transistors
Author(s) -
Nikiforov Gueorgui O.,
Venkateshvaran Deepak,
Mooser Sebastian,
Meneau Aurélie,
Strobel Thomas,
Kronemeijer Auke,
Jiang Lang,
Lee Mi Jung,
Sirringhaus Henning
Publication year - 2016
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201600163
Subject(s) - pentacene , materials science , joule heating , optoelectronics , transistor , current (fluid) , thin film transistor , threshold voltage , voltage , substrate (aquarium) , field effect transistor , nanotechnology , electrical engineering , composite material , engineering , layer (electronics) , oceanography , geology
The channel temperature ( T ch ) of solution‐processed 6,13‐ bis (triisopropylsilylethynyl)‐pentacene (TIPS pentacene) thin film transistors (TFTs) is closely monitored in real time during current–voltage ( I – V ) measurements carried out in a He exchange gas cryostat at various base temperatures ( T b ) between 300 K and 20 K. This is done using a platinum (Pt) resistance temperature sensor embedded within the transistor channel. Under large gate ( V g ) and source‐drain ( V ds ) voltage biases, an increase in T ch is observed, the magnitude of which depends on the thermal conductivity of the substrate. The increase in T ch is associated with a simultaneous increase in the transistor drain current ( I d ) and becomes particularly pronounced at cryogenic T b . These experimental observations are rationalized using a 1D theoretical model and are attributed to current‐induced Joule heating. However, even though the heating of the channel unquestionably plays an important role, the corresponding amount of increase in I d at cryogenic T b and large voltage biases cannot be fully accounted for unless at low temperatures μ TIPS is enhanced in the presence of strong electrical fields. Therefore it is concluded that the I – V characteristics of TIPS pentacene TFTs at low T b and large voltage biases are a result of a complex interplay between current‐induced Joule heating and electrical field effects.