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1.
《Microelectronic Engineering》2007,84(5-8):1003-1006
Nickel template is very suitable for thermal imprinting process since it has high mechanical durability and can easily be duplicated using electroforming technique. However nickel has a poor anti-sticking property; in addition, proper and stable releasing layer on nickel surface is not yet available.In this study, thin layer of SiO2 film was deposited on nickel surface and silane based hydrophobic self-assembled monolayer (SAM) was formed on SiO2 film, coated on nickel. Since the silane based SAM layer can be stably formed on SiO2 layer coated nickel template, it can be used anti-sticking layer for thermal imprint process using thermoplastic polymer resin or thermally curable prepolymer resin. 相似文献
2.
Jungwoo Shin Seon‐Jin Choi Inkun Lee Doo‐Young Youn Chong Ook Park Jong‐Heun Lee Harry L. Tuller Il‐Doo Kim 《Advanced functional materials》2013,23(19):2357-2367
Hierarchical SnO2 fibers assembled from wrinkled thin tubes are synthesized by controlling the microphase separation between tin precursors and polymers, by varying flow rates during electrospinning and a subsequent heat treatment. The inner and outer SnO2 tubes have a number of elongated open pores ranging from 10 nm to 500 nm in length along the fiber direction, enabling fast transport of gas molecules to the entire thin‐walled sensing layers. These features admit exhaled gases such as acetone and toluene, which are markers used for the diagnosis of diabetes and lung cancer. The open tubular structures facilitated the uniform coating of catalytic Pt nanoparticles onto the inner SnO2 layers. Highly porous SnO2 fibers synthesized at a high flow rate show five‐fold higher acetone responses than densely packed SnO2 fibers synthesized at a low flow rate. Interestingly, thin‐wall assembled SnO2 fibers functionalized by Pt particles exhibit a dramatically shortened gas response time compared to that of un‐doped SnO2 fibers, even at low acetone concentrations. Moreover, Pt‐decorated SnO2 fibers significantly enhance toluene response. These results demonstrate the novel and practical feasibility of thin‐wall assembled metal oxide based breath sensors for the accurate diagnosis of diabetes and potential detection of lung cancer. 相似文献
3.
《Progress in Photovoltaics: Research and Applications》2017,25(1):23-32
A thin SiOyNx film was inserted below a conventional SiNx antireflection coating used in c‐Si solar cells in order to improve the surface passivation and the solar cell's resistance to potential‐induced degradation (PID). The effect of varying the flow ratio of the N2O and SiH4 precursors and the deposition temperature for the SiOyNx thin film upon material properties were systematically investigated. An excellent surface passivation was obtained on FZ p‐type polished silicon wafers, with the best results obtained with a SiOyNx film deposited at a very low temperature of 130 °C and with an optical refractive index of 1.8. In the SiOyNx/SiNx stack structure, a SiOyNx film with ~6 nm thickness is sufficient to provide excellent surface passivation with an effective surface recombination velocity Seff < 2 cm/s. Furthermore, we applied the optimized SiOyNx/SiNx stack on multicrystalline Si solar cells as a surface passivation and antireflection coating, resulting in a 0.5% absolute average conversion efficiency gain compared with that of reference cells with conventional SiNx coating. Moreover, the cells with the SiOyNx/SiNx stack layers show a significant increase in their resistance to PID. Nearly zero degradation in shunt resistance was obtained after 24 h in a PID test, while a single SiNx‐coated silicon solar cell showed almost 50% degradation after 24 h. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
High‐Performance Amorphous Multilayered ZnO‐SnO2 Heterostructure Thin‐Film Transistors: Fabrication and Characteristics
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Su‐Jae Lee Chi‐Sun Hwang Jae‐Eun Pi Jong‐Heon Yang Chun‐Won Byun Hye Yong Chu Kyoung‐Ik Cho Sung Haeng Cho 《ETRI Journal》2015,37(6):1135-1142
Multilayered ZnO‐SnO2 heterostructure thin films consisting of ZnO and SnO2 layers are produced by alternating the pulsed laser ablation of ZnO and SnO2 targets, and their structural and field‐effect electronic transport properties are investigated as a function of the thickness of the ZnO and SnO2 layers. The performance parameters of amorphous multilayered ZnO‐SnO2 heterostructure thin‐film transistors (TFTs) are highly dependent on the thickness of the ZnO and SnO2 layers. A highest electron mobility of 43 cm2/V·s, a low subthreshold swing of a 0.22 V/dec, a threshold voltage of 1 V, and a high drain current on‐to‐off ratio of 1010 are obtained for the amorphous multilayered ZnO(1.5 nm)‐SnO2(1.5 nm) heterostructure TFTs, which is adequate for the operation of next‐generation microelectronic devices. These results are presumed to be due to the unique electronic structure of amorphous multilayered ZnO‐SnO2 heterostructure film consisting of ZnO, SnO2, and ZnO‐SnO2 interface layers. 相似文献
5.
Well‐aligned nanocrystalline (nc)‐Si/SiOx composite nanowires have been deposited on various substrates at 120 °C using SiCl4/H2 in a hot‐filament chemical vapor deposition reactor. Structural and compositional analyses reveal that silicon nanocrystals are embedded in the amorphous SiOx nanowires. The nc‐Si/SiOx composite nanowires are transparent in the range 500–900 nm. Photoluminescence spectra of the nc‐Si/SiOx composite nanowires have a broad emission band, ranging from 420 to 525 nm. Water vapor from the chamber wall plays a crucial role in the formation of the well‐aligned nanowires. A possible mechanism for the formation of the composite nanowires is suggested. 相似文献
6.
N. Drolet J.‐F. Morin N. Leclerc S. Wakim Y. Tao M. Leclerc 《Advanced functional materials》2005,15(10):1671-1682
We have fabricated organic field‐effect transistors based on thin films of 2,7‐carbazole oligomeric semiconductors 1,4‐bis(vinylene‐(N‐hexyl‐2‐carbazole))phenylene (CPC), 1,4‐bis(vinylene‐(N′‐methyl‐7′‐hexyl‐2′‐carbazole))benzene (RCPCR), N‐hexyl‐2,7‐bis(vinylene‐(N‐hexyl‐2‐carbazole))carbazole (CCC), and N‐methyl‐2,7‐bis(vinylene‐(7‐hexyl‐N‐methyl‐2‐carbazole))carbazole (RCCCR). The organic semiconductors are deposited by thermal evaporation on bare and chemically modified silicon dioxide surfaces (SiO2/Si) held at different temperatures varying from 25 to 200 °C during deposition. The resulting thin films have been characterized using UV‐vis and Fourier‐transform infrared spectroscopies, scanning electron microscopy, and X‐ray diffraction, and the observed top‐contact transistor performances have been correlated with thin‐film properties. We found that these new π‐conjugated oligomers can form highly ordered structures and reach high hole mobilities. Devices using CPC as the active semiconductor have exhibited mobilities as high as 0.3 cm2 V–1 s–1 with on/off current ratios of up to 107. These features make CPC and 2,7‐carbazolenevinylene‐based oligomers attractive candidates for device applications. 相似文献
7.
Stretchable Active Matrix Inorganic Light‐Emitting Diode Display Enabled by Overlay‐Aligned Roll‐Transfer Printing
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Minwoo Choi Bongkyun Jang Wonho Lee Seonwoo Lee Tae Woong Kim Hak‐Joo Lee Jae‐Hyun Kim Jong‐Hyun Ahn 《Advanced functional materials》2017,27(11)
An active matrix‐type stretchable display is realized by overlay‐aligned transfer of inorganic light‐emitting diode (LED) and single‐crystal Si thin film transistor (TFT) with roll processes. The roll‐based transfer enables integration of heterogeneous thin film devices on a rubber substrate while preserving excellent electrical and optical properties of these devices, comparable to their bulk properties. The electron mobility of the integrated Si‐TFT is over 700 cm2 V?1 s?1, and this is attributed to the good interface between the Si channel and the thermally grown SiO2 insulator. The light emission properties of the LED are of wafer quality. The resulting display stably operates under tensile strains up to 40%, over 200 cycles, demonstrating the potential of stretchable displays based on inorganic materials. 相似文献
8.
TixSi1xOy (TSO) thin films are fabricated using plasma‐enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub‐cycle ratio of TiO2 and SiO2. The refractive indices of SiO2 and TiO2 are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current‐voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films. 相似文献
9.
C. S. Kim S. J. Jo S. W. Lee W. J. Kim H. K. Baik S. J. Lee 《Advanced functional materials》2007,17(6):958-962
In this study, pentacene thin‐film transistors (TFTs) operating at low voltages with high mobilities and low leakage currents are successfully fabricated by the surface modification of the CeO2–SiO2 gate dielectrics. The surface of the gate dielectric plays a crucial role in determining the performance and electrical reliability of the pentacene TFTs. Nearly hysteresis‐free transistors are obtained by passivating the devices with appropriate polymeric dielectrics. After coating with poly(4‐vinylphenol) (PVP), the reduced roughness of the surface induces the formation of uniform and large pentacene grains; moreover, –OH groups on CeO2–SiO2 are terminated by C6H5, resulting in the formation of a more hydrophobic surface. Enhanced pentacene quality and reduced hysteresis is observed in current–voltage (I–V) measurements of the PVP‐coated pentacene TFTs. Since grain boundaries and –OH groups are believed to act as electron traps, an OH‐free and smooth gate dielectric leads to a low trap density at the interface between the pentacene and the gate dielectric. The realization of electrically stable devices that can be operated at low voltages makes the OTFTs excellent candidates for future flexible displays and electronics applications. 相似文献
10.
Gui Chen Zhe Liu Bo Liang Gang Yu Zhong Xie Hongtao Huang Bin Liu Xianfu Wang Di Chen Ming‐Qiang Zhu Guozhen Shen 《Advanced functional materials》2013,23(21):2681-2690
Zn3As2 is an important p‐type semiconductor with the merit of high effective mobility. The synthesis of single‐crystalline Zn3As2 nanowires (NWs) via a simple chemical vapor deposition method is reported. High‐performance single Zn3As2 NW field‐effect transistors (FETs) on rigid SiO2/Si substrates and visible‐light photodetectors on rigid and flexible substrates are fabricated and studied. As‐fabricated single‐NW FETs exhibit typical p‐type transistor characteristics with the features of high mobility (305.5 cm2 V?1 s?1) and a high Ion/Ioff ratio (105). Single‐NW photodetectors on SiO2/Si substrate show good sensitivity to visible light. Using the contact printing process, large‐scale ordered Zn3As2 NW arrays are successfully assembled on SiO2/Si substrate to prepare NW thin‐film transistors and photodetectors. The NW‐array photodetectors on rigid SiO2/Si substrate and flexible PET substrate exhibit enhanced optoelectronic performance compared with the single‐NW devices. The results reveal that the p‐type Zn3As2 NWs have important applications in future electronic and optoelectronic devices. 相似文献
11.
12.
Esteban Pedrueza José L. Valdés Vladimir Chirvony Rafael Abargues Jesús Hernández‐Saz Miriam Herrera Sergio I. Molina Juan P. Martínez‐Pastor 《Advanced functional materials》2011,21(18):3502-3507
SiO2 and TiO2 thin films with gold nanoparticles (NPs) are of particular interest as photovoltaic materials. A novel method for the preparation of spin‐coated SiO2–Au and TiO2–Au nanocomposites is presented. This fast and inexpensive method, which includes three separate stages, is based on the in situ synthesis of both the metal‐oxide matrix and the Au NPs during a baking process at relatively low temperature. It allows the formation of nanocomposite thin films with a higher concentration of Au NPs than other methods. High‐resolution transmission electron microscopy studies revealed a homogeneous distribution of NPs over the film volume along with their narrow size distribution. The optical manifestation of localized surface plasmon resonance was studied in more detail for TiO2‐based Au‐doped nanocomposite films deposited on glass (in absorption and transmittance) and silicon (in specular reflectance). Maxwell–Garnett effective‐medium theory applied to such metal‐doped nanocomposite films describes the peculiarities of the experimental spectra, including modification of the antireflective properties of bare TiO2 films deposited on silicon by varying the concentration of metal NPs. The antireflective capabilities of the film are increased after a wet etching process. 相似文献
13.
Kyung Whon Min Yong Kwan Kim Gunchul Shin Seunghun Jang Moonsup Han Junghwan Huh Gyu Tae Kim Jeong Sook Ha 《Advanced functional materials》2011,21(1):119-124
We report on the fabrication and optoelectronic properties of p‐n heterojunction arrays of p+‐type Si and aligned n‐type SnO2 nanowires with high rectification ratios of >104 at ±15 V. The electrical stability of the p‐n heterojunction devices was improved by coating the junction with poly(methylmethacrylate) to minimize the degradation of the interface layer at the junction. As a photodiode an enhanced UV photosensitivity higher than 102 was recorded under reverse bias. Using a large forward bias in the light‐emitting diode mode white light was emitted from the large‐scale heterojunction devices with at least three broad peaks in the visible range, which can be attributed to the interband transitions of the injected electrons or holes mediated by an interfacial SiO2 layer with a contribution of trap‐level energies. These results indicate the high potential of Si/SnO2 nanowires heterojunctions as optoelectronic devices with proper tuning of the recombination center at the junctions. 相似文献
14.
E. Fuentes-Fernandez W. Debray-Mechtaly M. A. Quevedo-Lopez B. Gnade A. Rajasekaran A. Hande P. Shah H. N. Alshareef 《Journal of Electronic Materials》2011,40(1):85-91
0.9Pb(Zr0.53,Ti0.47)O3-0.1Pb(Zn1/3,Nb2/3)O3 (PZT–PZN) thin films and integrated cantilevers have been fabricated. The PZT–PZN films were deposited on SiO2/Si or SiO2/Si3N4/SiO2/poly-Si/Si membranes capped with a sol–gel-derived ZrO2 buffer layer. It is found that the membrane layer stack, lead content, existence of a template layer of PbTiO3 (PT), and ramp rate during film crystallization are critical for obtaining large-grained, single-phase PZT–PZN films on the
ZrO2 surface. By controlling these parameters, the electrical properties of the PZT–PZN films, their microstructure, and phase
purity were significantly improved. PZT–PZN films with a dielectric constant of 700 to 920 were obtained, depending on the
underlying stack structure. 相似文献
15.
Do Hwan Kim Hwa Sung Lee Hoichang Yang Lin Yang Kilwon Cho 《Advanced functional materials》2008,18(9):1363-1370
To enhance the electrical performance of pentacene‐based field‐effect transistors (FETs) by tuning the surface‐induced ordering of pentacene crystals, we controlled the physical interactions at the semiconductor/gate dielectric (SiO2) interface by inserting a hydrophobic self‐assembled monolayer (SAM, CH3‐terminal) of organoalkyl‐silanes with an alkyl chain length of C8, C12, C16, or C18, as a complementary interlayer. We found that, depending on the physical structure of the dielectric surfaces, which was found to depend on the alkyl chain length of the SAM (ordered for C18 and disordered for C8), the pentacene nano‐layers in contact with the SAM could adopt two competing crystalline phases—a “thin‐film phase” and “bulk phase” – which affected the π‐conjugated nanostructures in the ultrathin and subsequently thick films. The field‐effect mobilities of the FET devices varied by more than a factor of 3 depending on the alkyl chain length of the SAM, reaching values as high as 0.6 cm2 V?1 s?1 for the disordered SAM‐treated SiO2 gate‐dielectric. This remarkable change in device performance can be explained by the production of well π‐conjugated and large crystal grains in the pentacene nanolayers formed on a disordered SAM surface. The enhanced electrical properties observed for systems with disordered SAMs can be attributed to the surfaces of these SAMs having fewer nucleation sites and a higher lateral diffusion rate of the first seeding pentacene molecules on the dielectric surfaces, due to the disordered and more mobile surface state of the short alkyl SAM. 相似文献
16.
Hui Huang Hua Gong Chee Lap Chow Jun Guo Timothy John White Man Siu Tse Ooi Kiang Tan 《Advanced functional materials》2011,21(14):2680-2686
Uniform SnO2 nanorod arrays have been deposited at low temperature by plasma‐enhanced chemical vapor deposition (PECVD). ZnO surface modification is used to improve the selectivity of the SnO2 nanorod sensor to H2 gas. The ZnO‐modified SnO2 nanorod sensor shows a normal n‐type response to 100 ppm CO, NH3, and CH4 reducing gas whereas it exhibits concentration‐dependent n–p–n transitions for its sensing response to H2 gas. This abnormal sensing behavior can be explained by the formation of n‐ZnO/p‐Zn‐O‐Sn/n‐SnO2 heterojunction structures. The gas sensors can be used in highly selective H2 sensing and this study also opens up a general approach for tailoring the selectivity of gas sensors by surface modification. 相似文献
17.
J. Schmidt A. Merkle R. Brendel B. Hoex M. C. M. van de Sanden W. M. M. Kessels 《Progress in Photovoltaics: Research and Applications》2008,16(6):461-466
Atomic‐layer‐deposited aluminium oxide (Al2O3) is applied as rear‐surface‐passivating dielectric layer to passivated emitter and rear cell (PERC)‐type crystalline silicon (c‐Si) solar cells. The excellent passivation of low‐resistivity p‐type silicon by the negative‐charge‐dielectric Al2O3 is confirmed on the device level by an independently confirmed energy conversion efficiency of 20·6%. The best results are obtained for a stack consisting of a 30 nm Al2O3 film covered by a 200 nm plasma‐enhanced‐chemical‐vapour‐deposited silicon oxide (SiOx) layer, resulting in a rear surface recombination velocity (SRV) of 70 cm/s. Comparable results are obtained for a 130 nm single‐layer of Al2O3, resulting in a rear SRV of 90 cm/s. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
18.
Effect of Spacer Length of Siloxane‐Terminated Side Chains on Charge Transport in Isoindigo‐Based Polymer Semiconductor Thin Films
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Jianguo Mei Hung‐Chin Wu Ying Diao Anthony Appleton Hong Wang Yan Zhou Wen‐Ya Lee Tadanori Kurosawa Wen‐Chang Chen Zhenan Bao 《Advanced functional materials》2015,25(23):3455-3462
A series of isoindigo‐based conjugated polymers (PII2F‐CmSi, m = 3–11) with alkyl siloxane‐terminated side chains are prepared, in which the branching point is systematically “moved away” from the conjugated backbone by one carbon atom. To investigate the structure–property relationship, the polymer thin film is subsequently tested in top‐contact field‐effect transistors, and further characterized by both grazing incidence X‐ray diffraction and atomic force microscopy. Hole mobilities over 1 cm2 V?1 s?1 is exhibited for all soluble PII2F‐CmSi (m = 5–11) polymers, which is 10 times higher than the reference polymer with same polymer backbone. PII2F‐C9Si shows the highest mobility of 4.8 cm2 V?1 s?1, even though PII2F‐C11Si exhibits the smallest π–π stacking distance at 3.379 Å. In specific, when the branching point is at, or beyond, the third carbon atoms, the contribution to charge transport arising from π–π stacking distance shortening becomes less significant. Other factors, such as thin‐film microstructure, crystallinity, domain size, become more important in affecting the resulting device's charge transport. 相似文献
19.
Jangdae Youn Geetha R. Dholakia Hui Huang Jonnathan W. Hennek Antonio Facchetti Tobin J. Marks 《Advanced functional materials》2012,22(9):1856-1869
The performance of bottom‐contact thin‐film transistor (TFT) structures lags behind that of top‐contact structures owing to the far greater contact resistance. The major sources of the contact resistance in bottom‐contact TFTs are believed to reflect a combination of non‐optimal semiconductor growth morphology on the metallic contact surface and the limited available charge injection area versus top‐contact geometries. As a part of an effort to understand the sources of high charge injection barriers in n‐channel TFTs, the influence of thiol metal contact treatment on the molecular‐level structures of such interfaces is investigated using hexamethyldisilazane (HMDS)‐treated SiO2 gate dielectrics. The focus is on the self‐assembled monolayer (SAM) contact surface treatment methods for bottom‐contact TFTs based on two archetypical n‐type semiconductors, α,ω‐diperfluorohexylquarterthiophene (DFH‐4T) and N,N′bis(n‐octyl)‐dicyanoperylene‐3,4:9,10‐bis(dicarboximide) (PDI‐8CN2). TFT performance can be greatly enhanced, to the level of the top contact device performance in terms of mobility, on/off ratio, and contact resistance. To analyze the molecular‐level film structural changes arising from the contact surface treatment, surface morphologies are characterized by atomic force microscopy (AFM) and scanning tunneling microscopy (STM). The high‐resolution STM images show that the growth orientation of the semiconductor molecules at the gold/SAM/semiconductor interface preserves the molecular long axis orientation along the substrate normal. As a result, the film microstructure is well‐organized for charge transport in the interfacial region. 相似文献
20.
P.V. Braun P. Osenar M. Twardowski G.N. Tew S.I. Stupp 《Advanced functional materials》2005,15(11):1745-1750
Aqueous gel‐like lyotropic liquid crystals with extensive hydrogen bonding and nanoscale hydrophilic compartments have been used to define the growth of macroscopic nanotemplated CdS and CdTe thin films. These mesoporous semiconductor films contain a hexagonal array of 2.5 nm pores, 7 nm center‐to‐center, that extend in an aligned fashion perpendicular to the substrate. The CdS is deposited on a polypropylene substrate by a reaction between Cd(NO3)2 dissolved in the liquid crystal and H2S transported via diffusion through the substrate. The CdTe is electrodeposited on indium‐tin‐oxide‐coated glass from TeO2 and Cd(NO3)2, both of which are dissolved in the liquid‐crystal template. The porous nature of the CdTe films enables chemical transformations of the entire bulk of the film. As electrodeposited, the CdTe films are Te rich and, in contrast to a non‐templated film, the excess Te could be removed via a chemical treatment, proving the continuity of the pores in the nanotemplated films. These results suggest that liquid‐crystal lithography with hydrogen‐bonding amphiphiles may be a useful approach to create materials with nanoscale features over macroscopic dimensions. 相似文献