Tuning of threshold voltage of organic field-effect transistors by space charge polarization

2009 ◽  
Vol 94 (7) ◽  
pp. 073304 ◽  
Author(s):  
Heisuke Sakai ◽  
Koudai Konno ◽  
Hideyuki Murata
Keyword(s):  
Space Charge ◽  
Threshold Voltage ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Space Charge Polarization ◽  
Organic Field Effect Transistors ◽  
Charge Polarization

Tuning the Threshold Voltage in Organic Field Effect Transistors by Space Charge Polarization of Gate Dielectrics

2009 ◽  
Vol 1154 ◽  
Author(s):  
Heisuke Sakai ◽  
Koudai Konno ◽  
Hideyuki Murata
Keyword(s):  
Space Charge ◽  
Active Layer ◽  
Threshold Voltage ◽  
Field Effect ◽  
Gate Dielectrics ◽  
Field Effect Transistors ◽  
Space Charge Polarization ◽  
Chemical Doping ◽  
Organic Field Effect Transistors ◽  
Charge Polarization

AbstractStudies of gate dielectrics in organic field effect transistors (OFETs) have been attractive because the electric properties of OFETs are susceptibly affected by the choice of the gate dielectrics. Here, we demonstrate a tunable threshold voltage in an organic field effect transistor (OFET) using an ion-dispersed gate dielectrics. By applying external electric field (Vex) to the gate dielectrics, the dispersed ions in the gate dielectrics are separated by electrophoresis and form space charge polarization. The drain current of the OFET increased over 1.9 times and the threshold voltage (Vth) decreased 22 V (from -35.1 V to -13.1 V).The shift direction of Vth was easily tuned by the polarity of the external voltage. The dielectric permittivity of the gate dielectrics and mobility of the active layer were unchanged after the polarization of the gate dielectrics. The UV-VIS differential absorption spectra of the OFETs indicate that there is no chemical doping in the active layer of the OFETs. These results indicated the shifts of threshold voltages were originated from the polarization of gate dielectrics.

Organic Field-Effect Transistors with a Low Pinch-Off Voltage and a Controllable Threshold Voltage

2008 ◽  
Vol 20 (3) ◽  
pp. 611-615 ◽  
Author(s):  
Y. Wang ◽  
Y. Q. Liu ◽  
Y. B. Song ◽  
S. H. Ye ◽  
W. P. Wu ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Organic Field Effect Transistors

Degradation of organic field-effect transistors made of pentacene

2004 ◽  
Vol 19 (7) ◽  
pp. 1999-2002 ◽  
Author(s):  
Ch. Pannemann ◽  
T. Diekmann ◽  
U. Hilleringmann
Keyword(s):  
Charge Carrier ◽  
Threshold Voltage ◽  
Field Effect ◽  
Gate Dielectric ◽  
Field Effect Transistors ◽  
Ambient Air ◽  
Organic Field Effect Transistors ◽  
Organic Thin Film ◽  
Field Effect Mobility ◽  
Semiconducting Material

This article reports degradation experiments on organic thin film transistors using the small organic molecule pentacene as the semiconducting material. Starting with degradation inert p-type silicon wafers as the substrate and SiO2 as the gate dielectric, we show the influence of temperature and exposure to ambient air on the charge carrier field-effect mobility, on-off-ratio, and threshold-voltage. The devices were found to have unambiguously degraded over 3 orders of magnitude in maximum on-current and charge carrier field-effect mobility, but they still operated after a period of 9 months in ambient air conditions. A thermal treatment was carried out in vacuum conditions and revealed a degradation of the charge carrier field-effect mobility, maximum on-current, and threshold voltage.

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