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Simultaneous determination of trap depth and the ratio of the rate of recombination to that of capture from thermo-luminescence

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Chinese Physics B 2006年第8期15卷 1883-1887页

作者：徐征张福俊赵谡玲王丽伟 A. N. Georgobiani V. B. Gutan 孟立建 Institute of Optoelectronics Key Laboratory of Luminescence and Optical Information Ministry of Education Beijing Jiaotong University Beijing 100044 China Departamento de Fisica Instituto Superior de Engenharia do Porto 4200-072 Porto Portugal P. N. Lebedev Physical Institute of Russian Academy of Sciences 117924 Moscow Russia

Thermo-luminescence （TL） is a kind of luminescence decay measured with varying temperature. In the process of TL the decay parameter itself involves the temperature effect of traps. Thus the trap depth is inseparable from the decay parameter. There are two separate peaks in the TL curve of ZnS：Cu,Co if the measurement starts from liquid nitrogen temperature. In the experiment we started from zero Celsius temperature to isolate the deeper traps. We have proposed and realized three methods for simultaneous determination of trap depth and decay parameter based on the quasi-equilibrium model and experimental data. If we treat the case of kinetic order a = 1 as a = 2, the error might be as large as 100%.

关键词： thermo-luminescence trap depth monomolecular and bimolecular processes

Setup of a dipole trap for all-optical trapping

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Chinese Physics B 2021年第5期30卷 362-366页

作者： Miao Wang Zheng Chen Yao Huang Hua Guan Ke-Lin Gao State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of SciencesWuhan 430071China Key Laboratory of Atomic Frequency Standards Wuhan Institute of Physics and MathematicsChinese Academy of SciencesWuhan 430071China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

Micromotion induced by the radio-frequency field contributes greatly to the systematic frequency shifts of optical frequency *** different strategies for mitigating this effect have been proposed,trapping ions optically has the potential to provide a generic solution to the elimination of *** could be achieved by trapping a single ion in the dipole trap composed of a highpower laser ***,we present the setup of the dipole trap composed of a 532 nm laser at a power of 10 W aiming to optically trap a single^(40)Ca^(+)and we observe an AC-Stark shift of the fluorescence spectrum line of~22 MHz caused by the 532 nm dipole *** beam waist of the dipole laser is several microns,which would provide a dipole potential strong enough for all-optical trapping of a single^(40)Ca^(+)ion.

关键词： dipole trap AC-Stark shift trap depth all-optical trapping

Enhanced afterglow performance of CaAl_(2)O_(4):Eu^(2+),Nd^(3+) phosphors by co-doping Gd^(3+)

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Journal of Rare Earths 2021年第8期39卷 930-937页

作者： Mingxi Zhang Fengfeng Li Yongcheng Lin Yan Li Yi Shen Light Alloy Research Institute of Central South University Changsha 410083China Key Laboratory of Inorganic Nonmetallic Materials Hebei Province Key Laboratory of Environment Functional Materials of Tangshan CityCollege of Materials Science and EngineeringNorth China University of Science and TechnologyTangshan 063210China School of Mechanical and Electrical Engineering.Central South University Changsha 410083China

In order to effectively improve the afterglow properties of CaAl_(2)O_(4):Eu^(2+),Nd^(3+) phosphors,a series of Ca_(0.982-x)Al_(2)O_(4):0.012 Eu^(2+),0.006 Nd^(3+),xGd^(3+)(x=0,0.012,0.024,0.036,0.048,0.060 mol) phosphors were prepared by a high-temperature solid-phase *** composition and microstructure were characterized by XRD,TEM,HRTEM,and XPS,luminescence properties were systematically analyzed by fluorescence spectra,afterglow decay curves and TL glow *** show that all of Ca_(0.982-x)Al_(2)O_(4):0.012 Eu^(2+),0.006 Nd^(3+),xGd^(3+)phosphors belong to monoclinic CaAl_(2)O_(4),without other cystalline *** blue emission at 442 nm is observed,which is assigned to the 4f^(6)5 d→4f^(7) transition of Eu^(2+) *** with appropriate amount of Gd^(3+) ions(x=0.036 mol) significantly improves the afterglow properties of phosphors,but the excessive doping of Gd^(3+) induces the fluorescent *** doping of moderate Gd^(3+) changes the traps states,the trap depth varies from 0.598 to 0.644 eV and the trap concentration is also greatly improved,thus significantly improving afterglow performance.

关键词： CaAl_(2)O_(4):Eu^(2+),Nd^(3+) Gd^(3+)ions Afterlow trap depth Mechanism Rare earths

Investigations into thermoluminescence and afterglow characterization of strontium aluminates with boron-modification and reductions via sol-gel route

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Journal of Rare Earths 2012年第10期30卷 972-978页

作者：陈一诚陈克恭陈弘森杜哲光林昭任林秀雄陈登铭谢天渝 Material Applications Center/IS Industrial Technology Research Institute College of Dental Medicine Kaohsiung Medical University Chemical Engineering Department National Chung-Cheng University Orthodontic Division Department of DentistryKaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine Applied Chemistry Department National Chiao Tung University

The effects of strontium aluminates of SrAl2O4：Eu2＋,Dy3＋（SAED） and boron-modified SAED （BSAED） phases synthesized from a sol-gel process on thermoluminescence （TL） along with their afterglow properties were systematically investigated with thermal activation in the different atmospheres. The result showed that the addition of boron and the reduction routes of Eu3＋to Eu2＋ in SrAl2O4：Dy3＋were related to phosphorescent decay properties. The aid of Dy3＋to induce the hole-trapping effect required both SAED and BSAED to be heated at 1300°C under the H2/N2（5%：95%） atmosphere. However, the trapping behavior of the reductions of SAED in nitrogen was similar to the compound without Dy3＋co-doping SrAl2O4：Eu2＋（SAE） in H2/N2（5%：95%）. BSAED showed deeper traps in situ compared to SAED which contained no boron, and this led to the better afterglow properties of BSAED than those of SAED. The afterglow spectrum of BSAED showed two peaks at 400±1 nm and 485±1 nm, which were two individuals composed and contributed from different depths of traps at 0.57 and 0.76eV, accordingly. The depth of the traps was calculated from the Hoogenstraaten’s plot of glow curves. The calculations for SAED and SAE were at around 0.43 and 0.18eV, respectively.

关键词： SrAl2O4:Eu2+,Dy3+ boron addition long afterglow thermoluminescence decay constant trap depth rare earths

Investigation of UV photosensor properties of Al-doped SnO_(2) thin films deposited by sol-gel dip-coating method

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Journal of Semiconductors 2023年第3期44卷 114-123页

作者： Kaour Selma Benkara Salima Bouabida Seddik Rechem Djamil Hadjeris Lazhar Laboratory of Materials and Structure of Electromechanical Systems and their Reliability Oum El Bouaghi UniversityAlgeria Faculty of Exact Sciences and Natural and Life Sciences Oum El Bouaghi UniversityAlgeria Electrical Engineering Department Oum El Bouaghi UniversityAlgeria Laboratory of Active Components and Materials Oum El Bouaghi UniversityAlgeria

Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystal-line with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scher-rer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uni-formly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an en-ergy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current-voltage characteristics, ION/IOFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.

关键词： tin oxide thin films sol-gel UV photodetector photoconductivity trap depth

Mechanism of oxide thickness and temperature dependent current conduction in n^+-polySi/SiO_2/p-Si structures—a new analysis

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Journal of Semiconductors 2017年第10期38卷 50-55页

作者： Baoxing Sun Ruobing Xie Cun Yu Cheng Li Hongjie Xu Piyas Samanta Department of Physics Vidyasagar College for Women 39 Sankar Ghosh Lane Kolkata 700006 India

The conduction mechanism of gate leakage current through thermally grown silicon dioxide（Si02）films on（100） p-type silicon has been investigated in detail under negative bias on the degenerately doped n-type polysilicon（n^＋-polySi） *** analysis utilizes the measured gate current density JG at high oxide fields Eox in5.4 to 12 nm thick Si02 films between 25 and 300 ℃.The leakage current measured up to 300 ℃ was due to Fowler-Nordheim（FN） tunneling of electrons from the accumulated n^＋-polySi gate in conjunction with Poole Frenkel（PF） emission of trapped-electrons from the electron traps located at energy levels ranging from 0.6 to 1.12 eV（depending on the oxide thickness） below the Si02 conduction band（CB）.It was observed that PF emission current IPF dominates FN electron tunneling current IFN at oxide electric fields EOX between 6 and 10 MV/cm and throughout the temperature range studied *** of the mechanism of leakage current conduction through Si02 films plays a crucial role in simulation of time-dependent dielectric breakdown（TDDB） of metaloxide-semiconductor（MOS） devices and to precisely predict the normal operating field or applied gate voltage for lifetime projection of the MOS integrated circuits.

关键词： FN tunneling PF emission image force lowering trap depth

The influence of K4Fe（CN）6 on the photosensitivity of cubic AgCl microcrystal

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Chinese Physics B 2005年第2期14卷 404-408页

作者：李晓苇刘荣鹃耿爱丛杨少鹏傅广生 CollegeofPhysicsScienceandTechnology HebeiUniversityBaoding071002China

The influence of K4Fe(CN)6 at various doping concentrations on the photosensitivity of cubic AgCl microcrystals has been investigated by using the microwave absorption and phase-sensitive measurement technique. The time behaviour of free photoelectrons in AgCl microcrystals is analysed by using computer simulation as a function of three parameters of shallow electron trap (SET) including doping concentration, trap depth and capture cross-section (CCS).It is found that the three parameters of SET play different roles on the free photoelectron decay time (FDT). After considering the threshold effects of the three parameters and their collective effects, the trap depth value, the CCS value,and the optimal doping concentration of the SET introduced by the dopant K4Fe(CN)6 in cubic AgCl microcrystals can also be determined, and the best photosensitivity of cubic AgCl can be obtained.

关键词： shallow electron trap photosensitivity trap depth doping concentration capture crosssection

Numerical Analysis of Space Charge Characteristics in Low-density Polyethylene Nanocomposite under External DC Electric Field

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Numerical Analysis of Space Charge Characteristics in Low-de...