Dependence of charge carrier injection on the interface energy barrier in short-channel polymeric field effect transistors

Alborghetti, S.; Coey, J. M. D.; Stamenov, Plamen

doi:10.1063/1.3701271

Cited by 19 publications

(15 citation statements)

References 22 publications

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“…The above discussion explains two observations; increase in resistance with time and increase of rate of increase of resistance on low level dispersing, very low change of resistance with time at higher concentration of 1% graphite. This is consistent with the observations reported by Mrunal S. Mahajan et al [5] that the conductivity of PEDOT-PSS film reduces on application of high electric field.…”

Section: Discussion On the Cause Of Resistance Increase After Applicasupporting

confidence: 93%

“…A metal semiconductor interface will form either a rectifying junction or an ohmic junction depending on the work functions of the semiconductor film and the contact metal [5][6][7][8]. When the interface is rectifying, the total resistance consists of two parts, the leakage resistance of a reverse biased diode and the bulk resistance of the film.…”

Section: Variation Of Resistance Of Pristine Pedot-pss Films With Timementioning

confidence: 99%

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Electric Field Induced Resistance Change in PEDOT-PSS Films

Bindu¹,

Suresh²

2017

BJAST

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Resistance of PEDOT-PSS films changes considerably with time after application of DC voltage. Since, variation of resistance over time can lead to serious errors when used as a strain gauge or gas sensors or any device, a detailed study of the variation of film resistance with time has been made. It has been observed that AC resistance is stable with time (constant) compared to DC resistance which has been explained in terms of contact diode model. It has also been found that doping with graphite leads to lower variation (better stabilization) in the resistance over time. The results indicate that the variation of resistance is an interfacial phenomenon at the contacts and either an ohmic contact or AC measurement removes this behavior. The change of resistance is attributable to high electric field in the interfacial region of the PEDOT-PSS/metal contact.

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Section: Discussion On the Cause Of Resistance Increase After Applicasupporting

confidence: 93%

Section: Variation Of Resistance Of Pristine Pedot-pss Films With Timementioning

confidence: 99%

Electric Field Induced Resistance Change in PEDOT-PSS Films

Bindu¹,

Suresh²

2017

BJAST

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“…Examples of contacts of P3HT on Au, Co, Py, Al, and Al 2 O 3 /Co indicated a well-formed valence band in the organic material in this type of short-channel FET devices. 28 When P3HT and the contact metals are brought together an energy barrier rises, which, in the simplest case, is just due to the difference between the ionization potential and work function of the two materials. In fact, previous studies indicated that two other limiting factors must be taken into account in determining the Schottky barrier height, namely the reduction of the electronic surface dipole contribution to the metal work function by organic adsorbed molecules, 29 which modify the Fermi level in the metal close to the interface, due the interaction with the organic molecules which compress the metal surface states, and a large density of localized interface trap-states due to morphological disorder in the first layer of the organic that pins the Fermi level in the polymer.…”

Section: P3htmentioning

confidence: 99%

“…In fact, previous studies indicated that two other limiting factors must be taken into account in determining the Schottky barrier height, namely the reduction of the electronic surface dipole contribution to the metal work function by organic adsorbed molecules, 29 which modify the Fermi level in the metal close to the interface, due the interaction with the organic molecules which compress the metal surface states, and a large density of localized interface trap-states due to morphological disorder in the first layer of the organic that pins the Fermi level in the polymer. 28,30 Charge carrier injection into the organic can occur, in parallel, both over and through the interface energy barrier, via the mechanisms of thermionic emission, typically dominant at high temperatures, and tunneling, respectively. The devices can be modeled by using the equivalent circuit model of Fig.…”

Section: P3htmentioning

confidence: 99%

Electron and spin transport studies of gated lateral organic devices

Alborghetti¹,

Coey²,

Stamenov³

2012

Journal of Applied Physics

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Articles you may be interested inSpin-dependent transport behavior in C60 and Alq3 based spin valves with a magnetite electrode (invited) J. Appl. Phys. 115, 172608 (2014) In view of the many, often contradictory, reports of magneto-resistance (MR) in spin valve stacks containing a layer of organic semiconductor, mostly of the small molecule variety, we have investigated interdigitated lateral structures with an organic layer deposited in the narrow gap between two ferromagnetic electrodes, which are well-suited for studying charge and spin transport in novel (high resistivity) semiconducting materials. For the channel material we used three different organic semiconductors, the small molecule tris-(8-hydroxyquinoline) aluminum (Alq3), single crystals of pentacene, and the conductive polymer poly(3-hexylthiophene) (P3HT). The channel length was 80 nm. Temperature-dependent current-voltage characteristics reveal that in all instances the current is limited by field-assisted thermionic injection over an energy barrier at the metal/organic interface. No measurable magneto-resistance was observed down to 7 K. The interface energy barrier, together with the vastly different electronic structure of metals and organics close to the Fermi level, preclude spin injection. Nonetheless, unlike the case of inorganic semiconductors, the insertion of an artificial tunnel barrier at the contact did not improve spin injection. Gate-dependent measurements exhibited shortchannel effects and transistor operation with on/off ratios of 10 3 , but no magneto-resistance. We suggest the observations are a consequence of the formation of bipolaron-states at increasing carrier concentration. V C 2012 American Institute of Physics. [http://dx

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“…The theory of metal-induced gap states for metal/ semiconductor interfaces has been invoked to account for the charge injection at metal/polymeric or organic dielectric interfaces [7,8], despite the lack of corresponding theoretical prediction and direct experimental evidence because of their difficulties for inherently disordered dielectric materials, unlike the case of ordered inorganic semiconductors. In addition, if the metal-induced gap states also truly exist in metal/dielectric interfaces, electrons would be transferred at a very low field by a thermal assistance from occupied metal-induced gap states to localized states of the dielectric and the Schottky emission would no longer be a required process for the electron transfer.…”

Section: Introductionmentioning

confidence: 99%

Low field thermally assisted charge injection at electrode/polyethylene interfaces observed by space charge measurements

Cang

Xuan

et al. 2013

2013 IEEE International Conference on Solid Dielectrics (ICSD)

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A layered sample consisting of a polyethylene (PE) film and a both surface fluorinated PE plate was used to investigate the charge injection at the semicon, Al, or Au electrode/PE interface by space charge observation based on the pressure wave propagation method, to determine whether it is a thermally assisted process. Space charge observation of the layered sample subjected to an averaged dc field of positive or negative 5 kV/mm shows that charge injection at the electrode/PE film interfaces occurs and charge accumulation at the film/surface fluorinated plate interface does not stop so long as the interface electric field is nonzero, independent of the electrode material. The charge injection and accumulation rates strongly depend on the poling temperature, showing a significant thermally assisted effect. A thermally assisted tunneling and/or thermal assistance of electrons from the occupied electrodeinduced gap states to the bulk states originating in PE itself can account for the observation of no threshold field for the charge injection.

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Dependence of charge carrier injection on the interface energy barrier in short-channel polymeric field effect transistors

Abstract: Articles you may be interested in Organic [6,6]-phenyl-C61-butyric-acid-methyl-ester field effect transistors: Analysis of the contact properties by combined photoemission spectroscopy and electrical measurements

Cited by 19 publications

References 22 publications

Electric Field Induced Resistance Change in PEDOT-PSS Films

Electric Field Induced Resistance Change in PEDOT-PSS Films

Electron and spin transport studies of gated lateral organic devices

Low field thermally assisted charge injection at electrode/polyethylene interfaces observed by space charge measurements

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