The charge storage characteristics of P-channel Ge/Si hetero-nanocrystal based MOSFET memory has been investigated and a logical array has been constructed using this memory cell. In the case of the thickness of tunne...The charge storage characteristics of P-channel Ge/Si hetero-nanocrystal based MOSFET memory has been investigated and a logical array has been constructed using this memory cell. In the case of the thickness of tunneling oxide Tox = 2 nm and the dimensions of Si- and Ge-nanocrystal Dsi = DGe = 5 nm, the retention time of this device can reach ten years(～1 × 108 s) while the programming and erasing time achieve the orders of microsecond and millisecond at the control gate voltage | Vg | = 3 V with respect to N-wells,respectively. Therefore, this novel device, as an excellent nonvolatile memory operating at room temperature,is desired to obtain application in future VLSI.展开更多
Techniques for detecting glucose are developing at a breathtaking speed because diabetes mellitus can cause many serious complications, such as blindness, high blood pressure heart disease and kidney failure. Herein, ...Techniques for detecting glucose are developing at a breathtaking speed because diabetes mellitus can cause many serious complications, such as blindness, high blood pressure heart disease and kidney failure. Herein, water sol- uble NaYF4：Eu^3＋@Ag core-shell nanocrystals for glucose de- tection with lower detection limit have been successfully de- veloped, using NaYF4：Eu^3＋ cores as the energy donors and Ag shells as the efficient quenchers through energy transfer. After immobilization of glucose oxidase （GOx） on the sur- face of NaYF4：Eu^3＋@Ag core-shell nanocrystals, the Ag shells can be decomposed in the presence of glucose, accompanied by down-shifting luminescence recovery. The limit of detec- tion of NaYF4：Eu^3＋@Ag was 0.12 μmol L^-1. Therefore, the NaYF4：Eu^3＋@Ag can be easily extended to the detection of a variety of H2O2-involved analytes.展开更多
Optical trapping techniques are of great interest since they have the advantage of enabling the direct handling of nanoparticles. Among various optical trapping systems, photonic crystal nanobeam cavities have attract...Optical trapping techniques are of great interest since they have the advantage of enabling the direct handling of nanoparticles. Among various optical trapping systems, photonic crystal nanobeam cavities have attracted great attention for integrated on-chip trapping and manipulation. However, optical trapping with high efficiency and low input power is still a big challenge in nanobeam cavities because most of the light energy is confined within the solid dielectric region. To this end, by incorporating a nanoslotted structure into an ultracompact one- dimensional photonic crystal nanobeam cavity structure, we design a promising on-chip device with ultralarge trapping potential depth to enhance the optical trapping characteristic of the cavity. In this work, we first provide a systematic analysis of the optical trapping force for an airborne polystyrene （PS） nanoparticle trapped in a cavity model. Then, to validate the theoretical analysis, the numerical simulation proof is demonstrated in detail by using the three-dimensional finite element method. For trapping a PS nanoparticle of 10 nm radius within the air-slot, a maximum trapping force as high as 8.28 nN/mW and a depth of trapping potential as large as 1.15 × 105 kBTmW-1 are obtained, where kB is the Boltzmann constant and T is the system temperature. We estimate a lateral trapping stiffness of 167.17 pN. nm-1 . mW-1 for a 10 nm radius PS nanoparticle along the cavity x-axis, more than two orders of magnitude higher than previously demonstrated on-chip, near field traps. Moreover, the threshold power for stable trapping as low as 0.087 μW is achieved. In addition, trapping of a single 25 nm radius PS nanoparticle causes a 0.6 nm redshift in peak wavelength. Thus, the proposed cavity device can be used to detect single nanoparticle trapping by monitoring the resonant peak wavelength shift. We believe that the architecture with features of an ultracompact footprint, high integrahility with optical waveguides/cir- cuits, and efficient trapping demonstrated here will provide a promising candidate for developing a lab-on-a-chip device with versatile functionalities.展开更多
One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile sy...One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects （e.g., nanocrystals） are necessary. Hence, a ＂library＂ dedicated to the preparation of various actinidebased nanoscale building blocks is currently being developed. Nanoscale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nanocrystals （both for thorium and uranium, and recently extended to neptunium and plutonium）. In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nanocrystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate （together with additional capping agents） into benzyl ether can be used to synthesize thorium/uranium mixed oxide nanocrystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium：uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nanocrystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nanocrystals of non-magnetic oxides as recently claimed in the literature.展开更多
文摘The charge storage characteristics of P-channel Ge/Si hetero-nanocrystal based MOSFET memory has been investigated and a logical array has been constructed using this memory cell. In the case of the thickness of tunneling oxide Tox = 2 nm and the dimensions of Si- and Ge-nanocrystal Dsi = DGe = 5 nm, the retention time of this device can reach ten years(～1 × 108 s) while the programming and erasing time achieve the orders of microsecond and millisecond at the control gate voltage | Vg | = 3 V with respect to N-wells,respectively. Therefore, this novel device, as an excellent nonvolatile memory operating at room temperature,is desired to obtain application in future VLSI.
基金supported by the National Natural Science Foundation of China(21471050 and 21501052)the China Postdoctoral Science Foundation(2015M570304)+2 种基金the Postdoctoral Science Foundation of Heilongjiang Province(LBH-TZ06019)the Natural Science Foundation of Heilongjiang Province(ZD201301d)the Science Foundation for Excellent Youth of Harbin City of China (2016RQQXJ099)
文摘Techniques for detecting glucose are developing at a breathtaking speed because diabetes mellitus can cause many serious complications, such as blindness, high blood pressure heart disease and kidney failure. Herein, water sol- uble NaYF4：Eu^3＋@Ag core-shell nanocrystals for glucose de- tection with lower detection limit have been successfully de- veloped, using NaYF4：Eu^3＋ cores as the energy donors and Ag shells as the efficient quenchers through energy transfer. After immobilization of glucose oxidase （GOx） on the sur- face of NaYF4：Eu^3＋@Ag core-shell nanocrystals, the Ag shells can be decomposed in the presence of glucose, accompanied by down-shifting luminescence recovery. The limit of detec- tion of NaYF4：Eu^3＋@Ag was 0.12 μmol L^-1. Therefore, the NaYF4：Eu^3＋@Ag can be easily extended to the detection of a variety of H2O2-involved analytes.
基金National Natural Science Foundation of China(NSFC)(61501053,61611540346,11474011,11654003,61435001,61471050,61622103)National Key R&D Program of China(2016YFA0301302)+1 种基金Fund of the State Key Laboratory of Information Photonics and Optical Communications(IPOC2017ZT05)Beijing University of Posts and Telecommunications,China
文摘Optical trapping techniques are of great interest since they have the advantage of enabling the direct handling of nanoparticles. Among various optical trapping systems, photonic crystal nanobeam cavities have attracted great attention for integrated on-chip trapping and manipulation. However, optical trapping with high efficiency and low input power is still a big challenge in nanobeam cavities because most of the light energy is confined within the solid dielectric region. To this end, by incorporating a nanoslotted structure into an ultracompact one- dimensional photonic crystal nanobeam cavity structure, we design a promising on-chip device with ultralarge trapping potential depth to enhance the optical trapping characteristic of the cavity. In this work, we first provide a systematic analysis of the optical trapping force for an airborne polystyrene （PS） nanoparticle trapped in a cavity model. Then, to validate the theoretical analysis, the numerical simulation proof is demonstrated in detail by using the three-dimensional finite element method. For trapping a PS nanoparticle of 10 nm radius within the air-slot, a maximum trapping force as high as 8.28 nN/mW and a depth of trapping potential as large as 1.15 × 105 kBTmW-1 are obtained, where kB is the Boltzmann constant and T is the system temperature. We estimate a lateral trapping stiffness of 167.17 pN. nm-1 . mW-1 for a 10 nm radius PS nanoparticle along the cavity x-axis, more than two orders of magnitude higher than previously demonstrated on-chip, near field traps. Moreover, the threshold power for stable trapping as low as 0.087 μW is achieved. In addition, trapping of a single 25 nm radius PS nanoparticle causes a 0.6 nm redshift in peak wavelength. Thus, the proposed cavity device can be used to detect single nanoparticle trapping by monitoring the resonant peak wavelength shift. We believe that the architecture with features of an ultracompact footprint, high integrahility with optical waveguides/cir- cuits, and efficient trapping demonstrated here will provide a promising candidate for developing a lab-on-a-chip device with versatile functionalities.
文摘One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects （e.g., nanocrystals） are necessary. Hence, a ＂library＂ dedicated to the preparation of various actinidebased nanoscale building blocks is currently being developed. Nanoscale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nanocrystals （both for thorium and uranium, and recently extended to neptunium and plutonium）. In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nanocrystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate （together with additional capping agents） into benzyl ether can be used to synthesize thorium/uranium mixed oxide nanocrystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium：uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nanocrystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nanocrystals of non-magnetic oxides as recently claimed in the literature.
