Monthly Archives: January 2015

Recent progress in high performance and reliable n-type transition metal oxide-based thin film transistors

This review gives an overview of the recent progress in vacuum-based n-type transition metal oxide (TMO) thin film transistors (TFTs). Several excellent review papers regarding metal oxide TFTs in terms of fundamental electron structure, device process and reliability have been published. In particular, the required field-effect mobility of TMO TFTs has been increasing rapidly to meet the demands of the ultra-high-resolution, large panel size and three dimensional visual effects as a megatrend of flat panel displays, such as liquid crystal displays, organic light emitting diodes and flexible displays. In this regard, the effects of the TMO composition on the performance of the resulting oxide TFTs has been reviewed, and classified into binary, ternary and quaternary composition systems. In addition, the new strategic approaches including zinc oxynitride materials, double channel structures, and composite structures have been proposed recently, and were not covered in detail in pr...

Oxygen plasma assisted high performance solution-processed Al2Ox gate insulator for combustion-processed InGaZnOx thin film transistors

The effects of oxygen-plasma treatment on solution-processed Al 2Ox gate dielectrics for InGaZnOx (IGZO) thin film transistors (TFTs) are investigated in this paper. Thin films of amorphous Al 2Ox are successfully fabricated by annealing temperature of 300 °C. Utilizing oxygen-plasma treated gate dielectrics, combustion-processed IGZO TFTs, which are annealed at a temperature of 300 °C, show a mobility of 7.3 cm2 V−1 s−1, a threshold voltage of −0.3 V, an on-off current ratio of 1 × 105, a subthreshold swing of 160 mV/decade, when operating with a voltage ranging from −2 V to +5 V. Our experimental results demonstrate that oxygen-plasma treatment can remarkably improve dielectric performance. This is presumably due to the passivation of interfacial and bulk traps, and the reduced concentration of oxygen vacancies.

Independent chemical/physical role of combustive exothermic heat in solution-processed metal oxide semiconductors for thin-film transistors

J. Mater. Chem. C, 2015, Advance ArticleDOI: 10.1039/C4TC02408G, CommunicationSeong Jip Kim, Ae Ran Song, Sun Sook Lee, Sahn Nahm, Youngmin Choi, Kwun-Bum Chung, Sunho JeongBased on newly-designed, solution-processable zinc tin oxide semiconductors, the independent contribution of combustive exothermic heat was investigated on chemical/physical structural evolution through spectroscopy analyses along with the interpretation on device performance.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry

Role of growth temperature on the frequency response characteristics of pentacene-based organic devices

The ac frequency response characteristics (FRC) of organic thin film transistors and metal-insulator semiconductor diodes were highly improved by controlling the morphology and electrical characteristics of semiconducting pentacene films. The devices with films grown at 50 °C show much higher cutoff frequency and better frequency stability of flat-band voltage, as compared to those with films grown at other temperatures below or above. The improvement mainly originates from the maximum field effect carrier mobility of 0.78 cm 2 V −1 s −1 and a small metal/organic contact resistance ( R c ) obtained in the optimum thin film transistors. Our results indicate growth temperature precisely tunes the film microstructure and metal/semiconductor interface, which together determine the FRC of pentacene-based organic devices.

Highly Stable and Imperceptible Electronics Utilizing Photoactivated Heterogeneous Sol-Gel Metal–Oxide Dielectrics and Semiconductors

Incorporation of Zr into AlOx matrix generates an intrinsically activated ZAO surface enabling formation of a stable semiconducting IGZO film and good interfacial property. Photochemically annealed metal–oxide devices and circuits with the optimized sol-gel ZAO dielectric and IGZO semiconductor layers demonstrate the high performance and electrically/mechanically stable operation of flexible electronics fabricate via low-temperature solution process.

Unusual loss of electron mobility upon furan for thiophene substitution in a molecular semiconductor

Publication date: March 2015 Source:Organic Electronics, Volume 18 Author(s): Arthur D. Hendsbee , Jon-Paul Sun , Theresa M. McCormick , Ian G. Hill , Gregory C. Welch Furan has often been considered as a more sustainable alternative to thiophene in organic electronics. Herein we demonstrate that replacing thiophene with furan in a phthalimide based molecular semiconductor results in a complete loss of electron mobility when evaluated using organic thin film transistors (OTFTs). Although optical, electronic, thermal, and structural characterization show subtle effects substituting furan for thiophene, theoretical dimer modeling employing the respective single crystal structures of the two molecules reveals a loss of degeneracy between the lowest unoccupied molecular orbital (LUMO) and LUMO+1 molecular orbitals in the bifuran-containing molecule. These results demonstrate that minor changes to molecular structure can result in large differences in device performance. Graphical abstract

Characterization of reactively sputtered c-axis aligned nanocrystalline InGaZnO 4

Crystallinity and texturing of RF sputtered c-axis aligned crystal InGaZnO4 (CAAC IGZO) thin films were quantified using X-ray diffraction techniques. Above 190 °C, nanocrystalline films with an X-ray peak at 2θ = 30° (009 planes) developed with increasing c-axis normal texturing up to 310 °C. Under optimal conditions (310 °C, 10% O2), films exhibited a c-axis texture full-width half-maximum of 20°. Cross-sectional high-resolution transmission electron microscopy confirmed these results, showing alignment variation of ±9° over a 15 × 15 nm field of view and indicating formation of much larger aligned domains than previously reported. At higher deposition temperatures, c-axis alignment was gradually lost as polycrystalline films developed.