Transparent metal oxide nanowires （NWs） have attracted intense research interest in recent years. We report here the synthesis of interesting ladder-like metal oxide NWs, including In2O3, SnO2, ZnO, and Ga2O3, via a...Transparent metal oxide nanowires （NWs） have attracted intense research interest in recent years. We report here the synthesis of interesting ladder-like metal oxide NWs, including In2O3, SnO2, ZnO, and Ga2O3, via a facile chemical vapor deposition （CVD） method. Their structural features and growth mechanism are demonstrated in detail by using the ladder-like In2O3 NWs as an example. Single ladder-like NW-based field-effect transistors （FETs） and photodetectors （PDs） of SnO2 were fabricated in order to investigate their electrical transport and light absorption properties. Compared with straight NW-based FETs which operate in an enhancement mode （E-mode）, FETs build on ladder-like NWs operate in a depletion mode （D-mode）. The ladder-like NWs also give higher carrier concentrations than conventional single nanowires. Finite-difference time-domain （FDTD） simulations have been performed on the ladder-like NWs and the results reveal a great enhancement of light absorption with both transverse-electric （TE） and transverse-magnetic （TM） polarization modes, which is in good agreement with the experimental results.展开更多
Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graph...Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors （GFETs）. Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a （deprotonating） hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system.展开更多
Various nanostructures of the organic semiconductor (OSC)films have been reported to enhance the organic field-effect transistors (OFETs)sensing performance. However,complicated fabrication processes hinder their ap- ...Various nanostructures of the organic semiconductor (OSC)films have been reported to enhance the organic field-effect transistors (OFETs)sensing performance. However,complicated fabrication processes hinder their ap- plications.In this work,we have effectively enhanced the sensitivity of the OFET-based sensors only by adjusting substrate temperature in OSC preparation and surface treatment of the dielectric layer.The relative sensitivity of the device can be enhanced by 5 times.The flexible sensors with polymer dielectric also exhibit high sensitivity because the less smooth surface of the polymer provides the OSCs with smaller grain size.Therefore,this work reveals the trade-off effects of the OSCs grain size on both transistor characteristic and chemic.al sensing performance,and provides a simple and extensively applicable strategy for OFETs sensitivity improvement.展开更多
Graphene has lots of applications, such as field-effect transistors, solar cells and transparent electrodes. In this work, we developed a new donor-acceptor graphene hybrid by covalently bonding a donor phenanthrene-9...Graphene has lots of applications, such as field-effect transistors, solar cells and transparent electrodes. In this work, we developed a new donor-acceptor graphene hybrid by covalently bonding a donor phenanthrene-9-carboxaldehyde (PCA) onto the acceptor graphene (PCA-graphene) via 1,3-dipolar cycloaddition azomethine ylides. The resulting PCA-graphene is soluble in N,N-dimethyformamide (DMF). The optoelectronic device (photoanode) fabricated by spin-coating DMF solution of the hybrids exhibits an enhanced photocurrent under visible irradiation.展开更多
基金This work was supported by the National Natural Science Foundation of China （Nos. 61377033 and 91123008）, the 973 Program of China （No. 2011CB933300）, and the Program for New Century Excellent Talents of the University in China （Grant No. NCET-11-0179）.
文摘Transparent metal oxide nanowires （NWs） have attracted intense research interest in recent years. We report here the synthesis of interesting ladder-like metal oxide NWs, including In2O3, SnO2, ZnO, and Ga2O3, via a facile chemical vapor deposition （CVD） method. Their structural features and growth mechanism are demonstrated in detail by using the ladder-like In2O3 NWs as an example. Single ladder-like NW-based field-effect transistors （FETs） and photodetectors （PDs） of SnO2 were fabricated in order to investigate their electrical transport and light absorption properties. Compared with straight NW-based FETs which operate in an enhancement mode （E-mode）, FETs build on ladder-like NWs operate in a depletion mode （D-mode）. The ladder-like NWs also give higher carrier concentrations than conventional single nanowires. Finite-difference time-domain （FDTD） simulations have been performed on the ladder-like NWs and the results reveal a great enhancement of light absorption with both transverse-electric （TE） and transverse-magnetic （TM） polarization modes, which is in good agreement with the experimental results.
基金This research was supported by the Nano/Bio Interface Center through the National Science Foundation Nanoscale Science and Engineering Center （NSEC） DMR08-32802, and the work involved use of its facilities. Support from Lockheed Martin is also gratefully acknowledged. M.L. acknowledges the support of the Science, Mathematics, And Research for Transformation （SMART） Fellowship.
文摘Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors （GFETs）. Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a （deprotonating） hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system.
基金supported by the National Natural Science Foundation of China (51603151 and 51741302)the National Key Research and Development Program of China (2017YFA0103900 & 2017YFA0103904)+1 种基金 Science & Technology Foundation of Shanghai (17JC1404600) the Fundamental Research Funds for the Central Universities.
文摘Various nanostructures of the organic semiconductor (OSC)films have been reported to enhance the organic field-effect transistors (OFETs)sensing performance. However,complicated fabrication processes hinder their ap- plications.In this work,we have effectively enhanced the sensitivity of the OFET-based sensors only by adjusting substrate temperature in OSC preparation and surface treatment of the dielectric layer.The relative sensitivity of the device can be enhanced by 5 times.The flexible sensors with polymer dielectric also exhibit high sensitivity because the less smooth surface of the polymer provides the OSCs with smaller grain size.Therefore,this work reveals the trade-off effects of the OSCs grain size on both transistor characteristic and chemic.al sensing performance,and provides a simple and extensively applicable strategy for OFETs sensitivity improvement.
基金supported by the National Natural Science Foundation of China (20920102034, 20877076 & 20907056)the National Basic Research Program of China (2010CB933503 & 2007CB613306)
文摘Graphene has lots of applications, such as field-effect transistors, solar cells and transparent electrodes. In this work, we developed a new donor-acceptor graphene hybrid by covalently bonding a donor phenanthrene-9-carboxaldehyde (PCA) onto the acceptor graphene (PCA-graphene) via 1,3-dipolar cycloaddition azomethine ylides. The resulting PCA-graphene is soluble in N,N-dimethyformamide (DMF). The optoelectronic device (photoanode) fabricated by spin-coating DMF solution of the hybrids exhibits an enhanced photocurrent under visible irradiation.
