APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

14 Sep 2009

Volume 95, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 95, 113101 (2009); http://dx.doi.org/10.1063/1.3197646 (3 pages)

Jesse J. Cole, En-Chiang Lin, Chad R. Barry, and Heiko O. Jacobs
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds
FREE

Polymer reptation for molecular assembly of copper phthalocyanine

Xiaoli Duan, Qingxin Tang, Jie Qiu, Yanhua Niu, Zhigang Wang, and Wenping Hu

Appl. Phys. Lett. 95, 113301 (2009); http://dx.doi.org/10.1063/1.3216040 (3 pages) | Cited 7 times

Online Publication Date: 15 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An efficient molecular assembly in vacuum and on solid state surface is demonstrated by using copper phthalocyanine (CuPc) as the candidate molecule wherein the assembly is dependent on the coassistance of the reptation of polymer chains and the π-π interactions of CuPc. The films assembled by this method exhibit high electronic performance, e.g., the carrier mobility based on the assembled CuPc films is improved by one order compared to that of the devices based on unassembled CuPc films, indicating their prospective application in organic electronics.
Show PACS
68.55.ag Semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
72.20.Fr Low-field transport and mobility; piezoresistance
73.61.Ph Polymers; organic compounds
85.65.+h Molecular electronic devices
FREE

Improved electrical stability in cyclically bent organic thin film transistors with nanocomposite gate dielectrics and surface passivation

H. Y. Noh, Y. G. Seol, and N.-E. Lee

Appl. Phys. Lett. 95, 113302 (2009); http://dx.doi.org/10.1063/1.3224909 (3 pages) | Cited 3 times

Online Publication Date: 16 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper investigates reliability improvements in cyclically bent bottom-gated pentacene organic thin film transistors by employing surface passivation as well as nanocomposite gate dielectrics. The variation in the hysteresis of the cyclically bent nanocomposite devices with increased Al2O3 nanoparticle fractions without surface passivation decreased. This was primarily attributed to the absence of change in charge trapping sites such as hydroxyl (OH) groups in the gate dielectrics due to reduced susceptibility of the nanocomposite dielectrics to penetration of water molecules. Furthermore, surface passivation of the devices by depositing organic thin films effectively improved their stability in the off-state current due to protection of the pentacene, which prevented penetration of ambient water.
Show PACS
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
73.61.Ph Polymers; organic compounds
81.65.Rv Passivation
77.80.Dj Domain structure; hysteresis
FREE

The impact of contact formation on the light emission from ambipolar transistors

Martin Schidleja, Christian Melzer, Michael Roth, Thorsten Schwalm, Christian Gawrisch, Matthias Rehahn, and Heinz von Seggern

Appl. Phys. Lett. 95, 113303 (2009); http://dx.doi.org/10.1063/1.3222976 (3 pages) | Cited 5 times

Online Publication Date: 16 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter the effect of the charge carrier injection on the performance of ambipolar light-emitting organic field-effect transistors will be investigated. For the analysis, the light output and spatial information of the recombination zone from different devices will be compared. The three investigated devices provide either Ohmic contacts for one or both charge carrier types or hindered injection for both. It will be demonstrated that the light emission in the different operation regimes of the transistor can be used to characterize the contact properties at source and drain.
Show PACS
85.30.Pq Bipolar transistors
FREE

Degradation of organic light emitting diodes by nucleated telephone cord blisters

Wali O. Akande and Wole Soboyejo

Appl. Phys. Lett. 95, 113304 (2009); http://dx.doi.org/10.1063/1.3227695 (3 pages) | Cited 1 time

Online Publication Date: 16 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter presents the results of a study into adhesion-related degradation mechanisms in single layer polymer light emitting diodes with poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] as the active layer. These studies reveal spiral-shaped blister patterns that are associated with rapid degradation of the device. Scanning electron microscopy and atomic force microscopy images of these defects reveal that these patterns are spiral telephone cord failures that form as a result of compressive stresses in the device.
Show PACS
85.60.Jb Light-emitting devices
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Ps Atomic force microscopy (AFM)
FREE

Phosphonic acid self-assembled monolayer and amorphous hafnium oxide hybrid dielectric for high performance polymer thin film transistors on plastic substrates

Orb Acton, Itaru Osaka, Guy Ting, Daniel Hutchins, Hong Ma, Richard D. McCullough, and Alex K.-Y. Jen

Appl. Phys. Lett. 95, 113305 (2009); http://dx.doi.org/10.1063/1.3231445 (3 pages) | Cited 8 times

Online Publication Date: 17 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A vacuum-free solution processed hybrid dielectric composed of an n-octadecyl-phosphonic acid self-assembled monolayer on amorphous sol-gel processed hafnium oxide (HfOx) is demonstrated for low-voltage polymer semiconductor-based thin film transistors (TFTs). The phosphonic acid/HfOx hybrid dielectric provides high capacitance (0.41 μF/cm2), low leakage current (5×10−8 A/cm2), and is compatible with plastic substrates. The utility of this dielectric is demonstrated by fabricating high performance polymer TFTs based on a spin coated thiophene-thiazolothiazole copolymer with operating voltages under −2 V, negligible hysteresis, subthreshold slopes as low as 100 mV/dec, and hole mobilities up to 0.11 cm2 V s.
Show PACS
85.30.Tv Field effect devices
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
FREE

Influence of ionization energy change on valence band offset in organic p-n junction

Kouki Akaike, Kaname Kanai, Yukio Ouchi, and Kazuhiko Seki

Appl. Phys. Lett. 95, 113306 (2009); http://dx.doi.org/10.1063/1.3231926 (3 pages) | Cited 5 times

Online Publication Date: 17 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Valence band offsets at [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/metallophthalocyanine (MPc, M = Cu and Zn) interfaces have been investigated with ultraviolet photoelectron spectroscopy, which are organic p-n junctions in organic photovoltaics. The highest occupied molecular orbitals of MPcs rise toward the interface, while that of PCBM lowers. This behavior implies that the different energy band offsets from inorganic p-n junction are realized in organic p-n junction. The depletion layers were not observed at the interfaces. Such anomalous energy band offsets are attributed to the interfacial dipole and also ionization energy changes of MPcs and PCBM at the interface.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
79.60.Jv Interfaces; heterostructures; nanostructures
FREE

Tuning of threshold voltage in organic field-effect transistors with hydrophobic gate dielectric using monoenergetic low-energy electron beams and triode corona

K. D. Deshmukh, K. Reuter, H. Kempa, J. E. West, and H. E. Katz

Appl. Phys. Lett. 95, 113307 (2009); http://dx.doi.org/10.1063/1.3222854 (3 pages) | Cited 6 times

Online Publication Date: 18 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report organic field-effect transistors (OFETs) with the hydrophobic gate dielectric exposed to an electron beam before semiconductor deposition, shifting the threshold voltage toward positive gate bias for a p-channel semiconductor. A 1 μm Cytop film was irradiated with defined doses of electron beams with different energies. The charges/polarizations embedded in the dielectric by the irradiation have effective charge densities of ∼ 10−8 C/cm2. OFETs were completed using 5,5′-bis(4-hexylphenyl)-2,2′-bithiophene as the semiconductor, and showed corresponding shifts in Vth. Other OFETs were made where the gate dielectric was treated with a corona discharge. Both types of devices showed similar shifts in Vth and transfer characteristics. There is no change in mobility of the charge carriers after either charging process. The charges do not contribute to the gate capacitance but induce changes in the onset of capacitance increase caused by accumulation of mobile channel charge during capacitance-voltage experiments in two-terminal metal-insulator-semiconductor-metal configurations.
Show PACS
85.30.Tv Field effect devices
FREE

Reduced contact resistances in organic transistors with secondary gates on source and drain electrodes

K. Nakayama, T. Uemura, M. Uno, and J. Takeya

Appl. Phys. Lett. 95, 113308 (2009); http://dx.doi.org/10.1063/1.3231927 (3 pages)

Online Publication Date: 18 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Secondary-gate electrodes under source and drain electrodes are introduced in organic thin-film transistors to reduce carrier-injection barriers into air-stable organic semiconductors. The additional gate electrodes buried in the gate insulators form “carrier-rich regions” in the vicinity of the source and drain electrodes with the application of sufficiently high local electric fields. Fabricating the structure with dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene, known for its excellent air stability, the contact resistance is drastically reduced especially at low gate voltages in the main channel. The result demonstrates carrier injection from the same material realizing a minimized potential barrier in the absence of interfacial trap levels for metal-to-semiconductor junctions.
Show PACS
85.30.Tv Field effect devices
81.05.Hd Other semiconductors
FREE

Three-dimensional fabrication of optically active microstructures containing an electroluminescent polymer

C. R. Mendonca, D. S. Correa, F. Marlow, T. Voss, P. Tayalia, and E. Mazur

Appl. Phys. Lett. 95, 113309 (2009); http://dx.doi.org/10.1063/1.3232207 (3 pages) | Cited 7 times

Online Publication Date: 18 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Microfabrication via two-photon absorption polymerization is a technique to design complex microstructures in a simple and fast way. The applications of such structures range from mechanics to photonics to biology, depending on the dopant material and its specific properties. In this paper, we use two-photon absorption polymerization to fabricate optically active microstructures containing the conductive and luminescent polymer poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). We verify that MEH-PPV retains its optical activity and is distributed throughout the microstructure after fabrication. The microstructures retain the emission characteristics of MEH-PPV and allow waveguiding of locally excited fluorescence when fabricated on top of low refractive index substrates.
Show PACS
42.86.+b Optical workshop techniques
42.70.Jk Polymers and organics
82.35.Cd Conducting polymers
42.79.Gn Optical waveguides and couplers
FREE

Self-assembled microarray of organic light-emitting diodes using a self-assembled monolayer by microcontact printing

Tae Hyun Park, Young Min Kim, Young Wook Park, Jin Hwan Choi, Jin-Wook Jeong, Kyung Cheol Choi, and Byeong-Kwon Ju

Appl. Phys. Lett. 95, 113310 (2009); http://dx.doi.org/10.1063/1.3222977 (3 pages) | Cited 3 times

Online Publication Date: 18 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A self-assembled microarray (SAMA) of organic light-emitting diodes (OLEDs) has been fabricated using self-assembled monolayers (SAMs) by microcontact printing (μCP). The hydrophobic methyl-terminated SAMs modify the surface properties of the substrates to become hydrophobic, i.e., with low surface energy. Thus, the hydrophobic SAMs pattern, by the μCP, can be applied to form SAMAs on the patterned SAMs since the difference of the local surface energy modifies the patterns on the substrates. In this study, octadecyltrichlorosilane based hydrophobic methyl-terminated SAMs have been used and the fabricated OLEDs, with the SAMAs show local light emissions on the micron scale with efficient performances.
Show PACS
85.60.Jb Light-emitting devices
85.40.Hp Lithography, masks and pattern transfer
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close