Abstract： In this work, the authors present a study of growth and characterization of composite based on AI and CNT （carbon nanotubes. The composites were prepared by a chemical mixing method and characterized by SE...Abstract： In this work, the authors present a study of growth and characterization of composite based on AI and CNT （carbon nanotubes. The composites were prepared by a chemical mixing method and characterized by SEM analysis, energy dispersed X-ray measurements, X-ray photoelectron spectroscopy and cathodoluminescence spectroscopy. The analysis showed that the composites are formed by macro-cluster of aluminum oxide on a network of CNT without formation of chemical bonds at interface between particles. The results are compared with those obtained for a sample of CNT with AI traces （〈 0.5%）. They show that only the presence of metal traces changes the nanotubes optical properties, with a luminescence signal centered at about 380 nm. These luminescence signals are caused by the adhesion between CNT and AI micro-clusters that promote the formation of band gap with some local energy levels.展开更多
Xenon atoms were produced in their metastable states 5p^56s[3/2]2 and 5p^56s＇[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p^5np＇ [3/2] 1,[1/2] 1...Xenon atoms were produced in their metastable states 5p^56s[3/2]2 and 5p^56s＇[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p^5np＇ [3/2] 1,[1/2] 1, and 5p^5nf＇ [5/2] 3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable 129Xe were obtained by recording the autoionized Xe＋ with time-of-flight ion detection in the photon energy range of 28000-42000 cm-1. A wealth of autoionizing resonances were newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects were derived.展开更多
We have measured the variation of photoluminescence(PL) in porous silicon with anodization(AO) time,HF soak time or natural oxidation time,and found that the peak value of PL spectrum will shift towards shorter value ...We have measured the variation of photoluminescence(PL) in porous silicon with anodization(AO) time,HF soak time or natural oxidation time,and found that the peak value of PL spectrum will shift towards shorter value as above time is increased.The analyses in experiment and theory show that the quantum confined structures produced by the AO process may be responsible for the blue shift.展开更多
Defects in Sb implanted Zn O single crystals have been studied by using photoluminescence(PL) spectroscopy,X-ray diffraction(XRD) and Raman scattering.Electrical properties of the samples were analyzed by Hall effect ...Defects in Sb implanted Zn O single crystals have been studied by using photoluminescence(PL) spectroscopy,X-ray diffraction(XRD) and Raman scattering.Electrical properties of the samples were analyzed by Hall effect measurement.The results indicate that the annealed Sb-implanted sample is n-type with a free electron concentration of the same amplitude as the calculated implantation concentration.The well-known oxygen vacancy related deep level green PL band is suppressed in the as-implanted sample and recovers to the level close to the as-grown Zn O single crystal after annealing.These phenomena suggest that a large portion of as-implanted Sb atoms occupy oxygen lattice site in an unstable state and move to the interstitial site,forming the complex donor defect upon high temperature annealing,resulting in n-type conduction even if the implantation dose is quite high.展开更多
文摘Abstract： In this work, the authors present a study of growth and characterization of composite based on AI and CNT （carbon nanotubes. The composites were prepared by a chemical mixing method and characterized by SEM analysis, energy dispersed X-ray measurements, X-ray photoelectron spectroscopy and cathodoluminescence spectroscopy. The analysis showed that the composites are formed by macro-cluster of aluminum oxide on a network of CNT without formation of chemical bonds at interface between particles. The results are compared with those obtained for a sample of CNT with AI traces （〈 0.5%）. They show that only the presence of metal traces changes the nanotubes optical properties, with a luminescence signal centered at about 380 nm. These luminescence signals are caused by the adhesion between CNT and AI micro-clusters that promote the formation of band gap with some local energy levels.
基金This work was supported by the National Natural Science Foundation of China （No.20673107）, the Chinese National Key Basic Research Special Foundation （No.2007CB815203）, and the Chinese Academy of Science （No.KJCX2-SW-H08）.
文摘Xenon atoms were produced in their metastable states 5p^56s[3/2]2 and 5p^56s＇[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p^5np＇ [3/2] 1,[1/2] 1, and 5p^5nf＇ [5/2] 3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable 129Xe were obtained by recording the autoionized Xe＋ with time-of-flight ion detection in the photon energy range of 28000-42000 cm-1. A wealth of autoionizing resonances were newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects were derived.
文摘We have measured the variation of photoluminescence(PL) in porous silicon with anodization(AO) time,HF soak time or natural oxidation time,and found that the peak value of PL spectrum will shift towards shorter value as above time is increased.The analyses in experiment and theory show that the quantum confined structures produced by the AO process may be responsible for the blue shift.
基金supported by the National Natural Science Foundation of China(Grant No.61474104)
文摘Defects in Sb implanted Zn O single crystals have been studied by using photoluminescence(PL) spectroscopy,X-ray diffraction(XRD) and Raman scattering.Electrical properties of the samples were analyzed by Hall effect measurement.The results indicate that the annealed Sb-implanted sample is n-type with a free electron concentration of the same amplitude as the calculated implantation concentration.The well-known oxygen vacancy related deep level green PL band is suppressed in the as-implanted sample and recovers to the level close to the as-grown Zn O single crystal after annealing.These phenomena suggest that a large portion of as-implanted Sb atoms occupy oxygen lattice site in an unstable state and move to the interstitial site,forming the complex donor defect upon high temperature annealing,resulting in n-type conduction even if the implantation dose is quite high.
