SiCx nano dots and nano wires with sizes from 60 nm to approximately 2μm were fabricated using liquid cell transmission electron microscope(TEM)technology.A SiCl_(4)in CH_(2)Cl_(2)solution was sealed between two piec...SiCx nano dots and nano wires with sizes from 60 nm to approximately 2μm were fabricated using liquid cell transmission electron microscope(TEM)technology.A SiCl_(4)in CH_(2)Cl_(2)solution was sealed between two pieces of Si_(3)N_(4)window grids in an in situ TEM liquid cell.Focused 200 keV electron beams were used to bombard the sealed precursors,which caused decomposition of the precursor materials,and deposition of the nano materials on the Si_(3)N_(4)window substrates.The size of nano dots increased with beam exposure time,following an approximately exponential relationship with the beam doses.Secondary electrons are attributed as the primary sources for the Si and C reduction.A nano device was formed from a deposited nano wire,with its electrical property characterized.展开更多
Several nano material and reaction systems were in situ monitored with an electrochemical TEM wet cell set up. In a 1 g/L sliver particle aqueous solution, the particles were observed to be ca. 10 nm sized, in both di...Several nano material and reaction systems were in situ monitored with an electrochemical TEM wet cell set up. In a 1 g/L sliver particle aqueous solution, the particles were observed to be ca. 10 nm sized, in both discrete particle and nano cluster forms. The silver particles were attached to the 50 nm-thick Si3N4 windows of the wet cell and could not move freely in the liquid. With a SIC14 liquid loaded in the wet cell, silicon nano materials were controllably grown on the wet cell windows by means of a liquid phase electron beam induced deposition （EBID） method. The deposited nano dots were nicely round-shaped, and demonstrated a power law growth dependency on beam exposure time in a log-log plot. In a NiCI2 solution/Ni system, both electrochemical deposition and dissolution of the nickel nano films were observed while applying electric biases on to the nickel electrodes in the wet cell. Instead of extensional growth on existing crystals, interestingly, it is more commonly observed that new nickel nano particles grow out in front of the existing film first and then merged into the film. The wet cell set up is demonstrated to be a versatile tool for nano liquid system research.展开更多
Working with a biased atomic force microscope(AFM)tip in the tapping mode under ambient atmosphere,attoliter(10^(-18) L)water droplet patterns have been generated on a patterned carbonaceous surface.This is essentiall...Working with a biased atomic force microscope(AFM)tip in the tapping mode under ambient atmosphere,attoliter(10^(-18) L)water droplet patterns have been generated on a patterned carbonaceous surface.This is essentially electrocondensation of water leading to charged droplets,as evidenced from electrostatic force microscopy measurements.The droplets are unusual in that they exhibit a highly corrugated surface and evaporate rather slowly,taking several tens of minutes.展开更多
基金The experiments have been carried out in part in the Frederick Seitz Materials Research Laboratory Central Facilities,University of Illinois,which are partially supported by the U.S.Department of Energy under grants DE-FG02-07ER46453 and DE-FG02-07ER46471The authors thank S.J.Dillon,Y.Liu,J.Mabon,K.-W.Noh,A.Shah,T.Shang,J.G.Wen,J.M.Zuo for the kind help.The project was supported by Shanghai Leading Academic Discipline Project(B502)+2 种基金Shanghai Key Laboratory Project(08DZ2230500)Fundamental Research Fund of ECUST,Science and Technology Commission of Shanghai Municipality Project(11nm0507000)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘SiCx nano dots and nano wires with sizes from 60 nm to approximately 2μm were fabricated using liquid cell transmission electron microscope(TEM)technology.A SiCl_(4)in CH_(2)Cl_(2)solution was sealed between two pieces of Si_(3)N_(4)window grids in an in situ TEM liquid cell.Focused 200 keV electron beams were used to bombard the sealed precursors,which caused decomposition of the precursor materials,and deposition of the nano materials on the Si_(3)N_(4)window substrates.The size of nano dots increased with beam exposure time,following an approximately exponential relationship with the beam doses.Secondary electrons are attributed as the primary sources for the Si and C reduction.A nano device was formed from a deposited nano wire,with its electrical property characterized.
文摘Several nano material and reaction systems were in situ monitored with an electrochemical TEM wet cell set up. In a 1 g/L sliver particle aqueous solution, the particles were observed to be ca. 10 nm sized, in both discrete particle and nano cluster forms. The silver particles were attached to the 50 nm-thick Si3N4 windows of the wet cell and could not move freely in the liquid. With a SIC14 liquid loaded in the wet cell, silicon nano materials were controllably grown on the wet cell windows by means of a liquid phase electron beam induced deposition （EBID） method. The deposited nano dots were nicely round-shaped, and demonstrated a power law growth dependency on beam exposure time in a log-log plot. In a NiCI2 solution/Ni system, both electrochemical deposition and dissolution of the nickel nano films were observed while applying electric biases on to the nickel electrodes in the wet cell. Instead of extensional growth on existing crystals, interestingly, it is more commonly observed that new nickel nano particles grow out in front of the existing film first and then merged into the film. The wet cell set up is demonstrated to be a versatile tool for nano liquid system research.
基金The authors thank Professor C.N.R.Rao,Fellow of Royal Society(FRS)for his encouragement.Support from the Department of Science and Technology,Government of India is gratefully acknowledged.N.K.acknowledges Council of Scientific and Industrial Research(CSIR)for funding.N.K.acknowledges Ritu for reading the manuscript.The authors thank Veeco India Nano-technology Laboratory at Jawaharlal Nehru Centre for Advanced Scientific Research(JNCASR)for the AFM facility.A.S.acknowledges INDO-US Science&Technology Forum(IUSSTF)for funding.
文摘Working with a biased atomic force microscope(AFM)tip in the tapping mode under ambient atmosphere,attoliter(10^(-18) L)water droplet patterns have been generated on a patterned carbonaceous surface.This is essentially electrocondensation of water leading to charged droplets,as evidenced from electrostatic force microscopy measurements.The droplets are unusual in that they exhibit a highly corrugated surface and evaporate rather slowly,taking several tens of minutes.
