The effect of neutral trap on tunneling currentin ultrathin MOSFETs is investigated by num erical analy- sis.The barrier variation arisen by neutral trap in oxide layer is described as a rectangular potential well in...The effect of neutral trap on tunneling currentin ultrathin MOSFETs is investigated by num erical analy- sis.The barrier variation arisen by neutral trap in oxide layer is described as a rectangular potential well in the con- duction band of Si O2 .The different barrier variation of an ultrathin metal- oxide- sem iconductor(MOS) structure with oxide thickness of4nm is numerically calculated.It is shown that the effect of neutral trap on tunneling cur- rent can not be neglected.The tunneling current is increased when the neutral trap exists in the oxide layer.This simple m odel can be used to understand the occurring mechanism of stress induced leakage current.展开更多
We have investigated the self-assembly and light emission properties of organic α- sexithiophene （α-6T） molecules on Ag（100） under different coverage by scanning tunneling microscopy （STM）. At very low coverag...We have investigated the self-assembly and light emission properties of organic α- sexithiophene （α-6T） molecules on Ag（100） under different coverage by scanning tunneling microscopy （STM）. At very low coverage, the α-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure. As the coverage is increased,α-6T molecules tend to pack side by side into a denser stripe structure. Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag（100） with the lower-layer stripe pattern serving as a template. Molecular fluorescence for α-6T molecules on Ag（100） at a coverage of five monolayers has been detected by light excitations, which indicates a well decoupled electronic states for the top-layer α-6T molecules. However, the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission. The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules. For intramolecular fluorescence to occur, the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.展开更多
We theoretically present the results for a scanning tunneling transport between a metallic tip and a Kondo lattice.We calculate the density of states(DOS)and the tunneling current and differential conductance(DC)under...We theoretically present the results for a scanning tunneling transport between a metallic tip and a Kondo lattice.We calculate the density of states(DOS)and the tunneling current and differential conductance(DC)under different conduction-fermion band hybridization and temperature in the Kondo lattice.It is found that the hybridization strength and temperature give asymmetric coherent peaks in the DOS separated by the Fermi energy.The corresponding current and DC intensity depend on the temperature and quantum interference effect among the c-electron and f-electron states in the Kondo lattice.展开更多
文摘The effect of neutral trap on tunneling currentin ultrathin MOSFETs is investigated by num erical analy- sis.The barrier variation arisen by neutral trap in oxide layer is described as a rectangular potential well in the con- duction band of Si O2 .The different barrier variation of an ultrathin metal- oxide- sem iconductor(MOS) structure with oxide thickness of4nm is numerically calculated.It is shown that the effect of neutral trap on tunneling cur- rent can not be neglected.The tunneling current is increased when the neutral trap exists in the oxide layer.This simple m odel can be used to understand the occurring mechanism of stress induced leakage current.
基金Author to whom correspondence should be addressed. E-mail： zcdong@ustc.edu.cn, FAX： ＋86-551-3600103 This work was supported by the National Basic Research Program of China （No.2006CB922003 and No.2011CB921402）, the Chinese Academy of Sciences （No.KJCX2.YW.H06）, and the National Natural Science Foundation of China （No.91021004, No.10574117, and No.10974186）.
文摘We have investigated the self-assembly and light emission properties of organic α- sexithiophene （α-6T） molecules on Ag（100） under different coverage by scanning tunneling microscopy （STM）. At very low coverage, the α-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure. As the coverage is increased,α-6T molecules tend to pack side by side into a denser stripe structure. Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag（100） with the lower-layer stripe pattern serving as a template. Molecular fluorescence for α-6T molecules on Ag（100） at a coverage of five monolayers has been detected by light excitations, which indicates a well decoupled electronic states for the top-layer α-6T molecules. However, the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission. The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules. For intramolecular fluorescence to occur, the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.
基金Supported by the National Natural Science Foundation of China under Grant No.11547203the Research Project of Education Department in Sichuan Province of China under Grant No.15ZB0457
文摘We theoretically present the results for a scanning tunneling transport between a metallic tip and a Kondo lattice.We calculate the density of states(DOS)and the tunneling current and differential conductance(DC)under different conduction-fermion band hybridization and temperature in the Kondo lattice.It is found that the hybridization strength and temperature give asymmetric coherent peaks in the DOS separated by the Fermi energy.The corresponding current and DC intensity depend on the temperature and quantum interference effect among the c-electron and f-electron states in the Kondo lattice.
