Silicon nanowire field-effect transistor(SiNW-FET)sensors possess the ability of rapid response,real-time,and label-free detection with high sensitivity and selectivity in the analysis of charged molecules.Their nano-...Silicon nanowire field-effect transistor(SiNW-FET)sensors possess the ability of rapid response,real-time,and label-free detection with high sensitivity and selectivity in the analysis of charged molecules.Their nano-scale size makes them well suited for ultralow detection of charged molecules,but also brings the uniformity fabrication challenging,thus limiting their large-scale application.By a horizontal control approach,highly controllable silicon nanowires arrays at the top of the silicon-on-insulator(SOI)wafer(T-SiNW)were developed in our previous work.To further improve the device uniformity,here a novel SiNW fabricated approach was carefully designed by the combination of horizontal and vertical control.The new silicon nanowires appeared at the bottom of the top silicon layer(B-SiNW).The B-SiNW has a relatively low requirement on the fabrication process and better device uniformity compared to T-SiNW.These improvements resulted in the B-SiNW device with a lower current fluctuation(4.1 nA with 5.1%variations)in the flowing liquid,compared to the T-SiNW device(4.4 nA with 11%variations).Further,in quantitative detection of 40 ng/mL MMP-9,the B-SiNW sensors provided larger signals and lower fluctuation(normalized average response value:0.57 with 4.2%variations),compared to the T-SiNW sensors(0.41 with 12.1%variations),thus indicating a more accurate bio-analysis application of the B-SiNW sensor.This work advances the nanowire sensor technology a step closer toward large-scale application to create stable sensing platforms in disease diagnosis and monitoring.展开更多
Vertically oriented nanowires(NWs)of single-crystalline wurtzite GaN have been fabricated on a-LiAlO_(2)(100)substrate coated with a Au layer,via a chemical vapor deposition process at 1000℃ using gallium and ammonia...Vertically oriented nanowires(NWs)of single-crystalline wurtzite GaN have been fabricated on a-LiAlO_(2)(100)substrate coated with a Au layer,via a chemical vapor deposition process at 1000℃ using gallium and ammonia as source materials.The GaN NWs grow along the nonpolar[10]direction with steeply tapering tips,and have triangular cross-sections with widths of 50100 nm and lengths of up to several microns.The GaN NWs are formed by a vapor liquid solid growth mechanism and the tapering tips are attributed to the temperature decrease in the final stage of the synthesis process.The aligned GaN NWs show blue-yellow emission originating from defect levels,residual impurities or surface states of the GaN NWs,and have potential applications in nanotechnology.展开更多
基金the support from the National Key Research and Development Program of China(Nos.2018YFA0208500 and 2017YFA0207103).
文摘Silicon nanowire field-effect transistor(SiNW-FET)sensors possess the ability of rapid response,real-time,and label-free detection with high sensitivity and selectivity in the analysis of charged molecules.Their nano-scale size makes them well suited for ultralow detection of charged molecules,but also brings the uniformity fabrication challenging,thus limiting their large-scale application.By a horizontal control approach,highly controllable silicon nanowires arrays at the top of the silicon-on-insulator(SOI)wafer(T-SiNW)were developed in our previous work.To further improve the device uniformity,here a novel SiNW fabricated approach was carefully designed by the combination of horizontal and vertical control.The new silicon nanowires appeared at the bottom of the top silicon layer(B-SiNW).The B-SiNW has a relatively low requirement on the fabrication process and better device uniformity compared to T-SiNW.These improvements resulted in the B-SiNW device with a lower current fluctuation(4.1 nA with 5.1%variations)in the flowing liquid,compared to the T-SiNW device(4.4 nA with 11%variations).Further,in quantitative detection of 40 ng/mL MMP-9,the B-SiNW sensors provided larger signals and lower fluctuation(normalized average response value:0.57 with 4.2%variations),compared to the T-SiNW sensors(0.41 with 12.1%variations),thus indicating a more accurate bio-analysis application of the B-SiNW sensor.This work advances the nanowire sensor technology a step closer toward large-scale application to create stable sensing platforms in disease diagnosis and monitoring.
基金the National Natural Science Foundation of China(50525207 and 10374092)the National Basic Research Program of China(2007CB936601).
文摘Vertically oriented nanowires(NWs)of single-crystalline wurtzite GaN have been fabricated on a-LiAlO_(2)(100)substrate coated with a Au layer,via a chemical vapor deposition process at 1000℃ using gallium and ammonia as source materials.The GaN NWs grow along the nonpolar[10]direction with steeply tapering tips,and have triangular cross-sections with widths of 50100 nm and lengths of up to several microns.The GaN NWs are formed by a vapor liquid solid growth mechanism and the tapering tips are attributed to the temperature decrease in the final stage of the synthesis process.The aligned GaN NWs show blue-yellow emission originating from defect levels,residual impurities or surface states of the GaN NWs,and have potential applications in nanotechnology.
