Liping You

Precipitation and crystallization of nanometer Si clusters in annealed Si-rich SiO2 films

Si-rich SiO2 films with three different degrees of Si-richness were deposited by RF magnetron sputtering using Si-SiO2 composite targets. X-ray photoelectron spectroscopy measurements indicate that Si clusters were present in the as-deposited films. The precipitation and crystallization of nanometer Si clusters in SiO2 films annealed at high temperatures have been studied using high-resolution transmission electron microscopy and electron diffraction. Si nanocrystallites were observed in the sample deposited using a Si-SiO2 composite target having a 30% area of Si and which had been annealed at 900 degrees C. The average size and density of Si nanocrystallites in the films increased notably as the annealing temperature was increased from 900 to 1100 degrees C, Thus, using a 1100 degrees C anneal and increasing the area percentage of Si in the composite target from 20 to 30%, the average size of Si nanocrystallites increased about 15%, and the density of Si nanocrystallites increased by a factor of about 2.5

Slowing Down DNA Translocation Through Solid-State Nanopores by Pressure

The effect of applied pressure on event duration distributions in 3 kb dsDNA translocation is systematically investigated. The effects of pressure magnitude and nanopore size on the length discrimination between 615 bp and 1.14 kbp dsDNA is studied. The pressure-controlled DNA translocation in solid-state nanopores makes a significant contribution to improve the temporal resolution in DNA single-molecule detection.

In situ study of the growth of ZnO nanosheets using environmental scanning electron microscope

The authors demonstrated an investigation of the real-time growth of ZnO nanosheets via in situ observation in an environmental scanning electron microscope. It was found that ZnO nanosheets were grown in a two-stage process: [21¯1¯0]-oriented nanowires were grown first, and then ZnO nanosheets grew perpendicularly on the parent nanowires along the [0001] axis. The authors’ results revealed that the change of the ZnO growth direction from [21¯1¯0] (a axis) to [0001] (c axis) can be achieved by control of the growth temperature.The authors demonstrated an investigation of the real-time growth of ZnO nanosheets via in situ observation in an environmental scanning electron microscope. It was found that ZnO nanosheets were grown in a two-stage process: [21¯1¯0]-oriented nanowires were grown first, and then ZnO nanosheets grew perpendicularly on the parent nanowires along the [0001] axis. The authors’ results revealed that the change of the ZnO growth direction from [21¯1¯0] (a axis) to [0001] (c axis) can be achieved by control of the growth temperature.

Electroluminescence from Au/(nanoscale Ge/nanoscale SiO2) superlattices/p-Si

Nanoscale Ge/nanoscale SiO2 superlattices (SLs) with four periods have been grown using the two-electron-beam alternation evaporating technique. Visible electroluminescence (EL) from the semitransparent Au film/(nanoscale Ge/nanoscale SiO2) SL/p-Si structures was observed when the forward bias exceeded 5 V, and their EL power efficiencies were significantly higher than that of a semitransparent Au film/nanoscale Ge particles embedded SiO2 film/p-Si structure. The effects of thicknesses of nanoscale Ge layers in the SLs and of annealing temperatures on the EL were studied. It is found that the intensity and position of the major EL peak being located in a range of 640-680 nm vary synchronously, while the EL shoulder around 520 nm remains unchanged in wavelength with increasing Ge layer thickness. The results strongly support the viewpoint that EL originates from the luminescence centers in the SiO2 layers