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1.
A two-channel photo-acoustic spectrometer (PA spectrometer) with a near infrared diode laser was used for taking measurements
of a high resolution ethylene absorption spectrum. A semiconductor TEC-100 laser with an outer resonator generates a continuous
single-frequency radiation in the range 6030–6300 cm-1. A newly designed model of photo-acoustic detector (PAD) in the form of a ring type resonator provides for measurement of
weak absorption cross-section equal to 4×10-23 cm2/mol at a laser radiation power of 3 mW. The PAD threshold sensitivity is 2×10-9 cm-1 Hz-1/2 W, when the signal to noise ratio equals to 1.
The ethylene absorption spectrum within the range 6035–6210 cm-1 was measured for the first time with a spectral resolution of 10 MHz. The reported line centre positions have an uncertainty
of ± 0.0005 cm-1. The precise measurements of ethylene absorption cross-sections were carried out using the mixture of high purity ethylene
and broadening gas (nitrogen) at the mixture ratio 1:50–1:200. Measurements were carried out at a mixture pressure of about
4.2 kPa.
PACS 42.62.Fi; 42.55.Px 相似文献
2.
From thirty-nine combination difference equations we have determined three significant ground-vibronic state constants of silane: β 0/hc=2·85941 cm-1, γ 0/hc=-3·82×10-5 cm-1 and ε 0/hc=-7·97×10-7 cm-1 or in Hecht's notation B 0=2·85941 cm-1, D s=3·82×10-5 cm-1 and D t=2·436×10-6 cm-1. 相似文献
3.
采用离子注入法制备了钴离子掺杂的金红石相TiO2样品;离子注入能量、注量分别为40 keV(1×1016cm-2),80 keV(5×1015,1×1016,5×1016,1×1017cm-2),120 keV(1×1016cm-2). 通过XRD,XPS和UV-Vis等手段对掺杂前后样品的结构和光学性能进行了表征,分析了掺杂元素在金红石TiO2中的存在形式. XRD测试表明随着注入能量的增加晶体的损伤程度增加. UV-Vis测试表明掺杂后所有样品在可见光区的吸收增强; 并且随着注量的增加,注量为5×1015cm-2到5×1016cm-2范围内注入样品的光学带隙逐渐变小.
关键词:
钴
二氧化钛
离子注入
掺杂 相似文献
4.
An ultra-sensitive photo-acoustic spectrometer using a 10.4 μm broadly tunable mid-IR external cavity quantum cascade laser (EC-QCL) coupled with optical feedback to an optical power buildup cavity with high reflectivity mirrors was developed and tested. A laser optical power buildup factor of 181 was achieved, which corresponds to an intra-cavity power of 9.6 W at a wavelength of 10.4 μm. With a photo-acoustic resonance cell placed inside the cavity this resulted in the noise-equivalent absorption coefficient of 1.9 × 10?10 cm?1 Hz?1/2, and a normalized noise-equivalent absorption of 1.1 × 10?11 cm?1 W Hz?1/2. A novel photo-acoustic signal normalization technique makes the photo-acoustic spectrometer’s response immune to changes and drifts in the EC-QCL excitation power, EC-QCL to cavity coupling efficiency and cavity mirrors aging and contamination. An automatic lock of the EC-QCL to the cavity and optical feedback phase optimization permitted long wavelength scans within the entire EC-QCL spectral tuning range. 相似文献
5.
Absorption cross sections of argon for argon resonance radiation have been measured by several techniques. The apparent cross sections are small (0·1 to 1·6 × 10-18 cm2) for resonance absorption and the values depend on the technique used for measurement. These observations are interpreted in terms of extensive reversal and broadening in the source. The excitation and quenching of resonance fluorescence was studied to provide information about the rates of the processes The rate constants were estimated relative to k r, the rate constant for radiation. Radiation imprisonment leads to a reduction of k r from its natural value and observations of the decay of resonance fluorescence suggest that k r ~ 1·5 × 105 s-1 in our system at [Ar] = 2 × 1017 atom cm-3. Combining this value with the relative values for the quenching rate constants gives k 1 < 1·5 × 10-13, k 1′(M = N2) ~ 6 × 10-12, k 1′(M = NO) ~ 4 × 10-10, in units of cm3 s-1 molecule-1. 相似文献
6.
7.
Alexander V. Ivanishchev Alexei V. Churikov Irina A. Ivanishcheva Arseni V. Ushakov 《Ionics》2016,22(4):483-501
In order to establish the mechanism and to determine the parameters of lithium transport in electrodes based on lithium-vanadium phosphate (Li3V2(PO4)3), the kinetic model was designed and experimentally tested for joint analysis of electrochemical impedance (EIS), cyclic voltammetry (CV), pulse chronoamperometry (PITT), and chronopotentiometry (GITT) data. It comprises the stages of sequential lithium-ion transfer in the surface layer and the bulk of electrode material’s particles, including accumulation of lithium in the bulk. Transfer processes at both sites are of diffusion nature and differ significantly, both by temporal (characteristic time, τ) and kinetic (diffusion coefficient, D) constants. PITT data analysis provided the following D values for the predominantly lithiated and delithiated forms of the intercalation material: 10?9 and 3 × 10?10 cm2 s?1, respectively, for transfer in the bulk and 10?12 cm2 s?1 for transfer in the thin surface layer of material’s particles. D values extracted from GITT data are in consistency with those obtained from PITT: 3.5–5.8 × 10?10 and 0.9–5 × 10?10 cm2 s?1 (for the current and currentless mode, respectively). The D values obtained from EIS data were 5.5 × 10?10 cm2 s?1 for lithiated (at a potential of 3.5 V) and 2.3 × 10?9 cm2 s?1 for delithiated (at a potential 4.1 V) forms. CV evaluation gave close results: 3 × 10?11 cm2 s?1 for anodic and 3.4 × 10?11 cm2 s?1 for cathodic processes, respectively. The use of complex experimental measurement procedure for combined application of the EIS, PITT, and GITT methods allowed to obtain thermodynamic E,c dependence of Li3V2(PO4)3 electrode, which is not affected by polarization and heterogeneity of lithium concentration in the intercalate. 相似文献
8.
Investigation of AlGaN/GaN fluorine plasma treatment enhancement-mode high electronic mobility transistors by frequency-dependent capacitance and conductance analysis 下载免费PDF全文
This paper reports fluorine plasma treatment enhancement-mode HEMTs (high electronic mobility transistors) EHEMTs and conventional depletion-mode HEMTs DHEMTs fabricated on one wafer using separate litho-photography technology. It finds that fluorine plasma etches the AlGaN at a slow rate by capacitance--voltage measurement. Using capacitance--frequency measurement, it finds one type of trap in conventional DHEMTs with τT=(0.5-6) ms and DT= (1 - 5) × 1013 cm-2·eV-1. Two types of trap are found in fluorine plasma treatment EHEMTs, fast with τT(f)=(0.2-2) μs and slow with τT(s)=(0.5-6) ms. The density of trap states evaluated on the EHEMTs is DT(f)=(1 - 3) × 1012 cm-2·eV-1 and DT(s)=(2 - 6) × 1012 cm-2·eV-1 for the fast and slow traps, respectively. The result shows that the fluorine plasma treatment reduces the slow trap density by about one order, but introduces a new type of fast trap. The slow trap is suggested to be a surface trap, related to the gate leakage current. 相似文献
9.
本文在20°—300°K研究了室温载流子浓度2×1012—1×1020cm-3含硼或磷(砷)Si的电学性质。对一些p-Si样品用弱场横向磁阻法及杂质激活能法进行了补偿度的测定,并进行了比较。从霍尔系数与温度关系的分析指出,对于较纯样品,硼受主能级的电离能为0.045eV,磷施主能级为0.045eV,在载流子浓度为1018—1019cm-3时发现了费米简并,对载流子浓度为2×1017—1×1018cm-3的p-Si及5×1017—4×1018cm-3的n-Si观察到了杂质电导行为。从霍尔系数与电导率计算了非本征的霍尔迁移率。在100°—300°K间,晶格散射迁移率μ满足关系式AT-a,其中A=2.1×109,α=2.7(对空穴);或A=1.2×108,α=2.0(对电子)。另外,根据我们的材料(载流子浓度在5×1011—5×1020cm-3间),分别建立了一条电阻率与载流子浓度及电阻率与迁移率的关系曲线,以提供制备材料时参考之用。 相似文献
10.
Recombination of charge carriers in a?SiHx Schottky barriers with density of states near mid-gap ranging from 2.8×1015?7×1016cm-1eV-1 is attributed to recombination centers with hole capture cross-section of 1.3×10-15cm2. 相似文献
11.
《Solid State Ionics》1988,31(1):49-54
Annealing effects on the conductivity of KDP (KH2PO4) samples prepared either by melting under slight pressure (5.7 kgf/cm2) or by powder compression (1.3 × 103kgf/cm2) were studied in air by complex impedance spectroscopy. In both cases, annealing at 423 K reduces the conductivities to constant values: from 6.2 × 10 −6 to 1.6 × 10−7 Ω−1 cm−1 for samples prepared by melting and from 1.9 × 10∼7 to 6.1 × 10∼8 Ω−1 cm−1 for samples prepared by compression. Heating KDP at about 500 K significantly modifies its electric properties. Two relaxation processes are observed after this treatment. One of them is associated with a fairly strong dielectric polarizability. A small conductivity jump is observed close to 440 K. 相似文献
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14.
The pure rotational Raman spectrum of 11BF3 has been photographed. Great care was taken in the analysis to consider all the unresolved components under each observed Raman line profile. If this is ignored, systematic errors result. The final set of molecular constants obtained was B0 = 0.34502(±3 × 10?5)cm?1, DJ = 4.38(±0.10) × 10?7cm?1, and DJK = ?9.1(±1.0) × 10?7cm?1. 相似文献
15.
GaP(001) cleaned by argon-ion bombardment and annealed at 500°C showed the Ga-stabilized GaP(001)(4 × 2) structure. Only treatment in 10?5 Torr PH3 at 500°C gave the P-stabilized GaP(001)(1 × 2) structure. The AES peak ratio is 2 for the (4 × 2) and 3.5 for the (1 × 2) structure. Cs adsorbs with a sticking probability of unity up to 5 × 1014 Cs atoms cm?2 and a lower one at higher coverages. The photoemission measured with uv light of 3660 Å showed a maximum at the coverage of 5 × 1014 atoms cm?2. Cs adsorbs amorphously at room temperature, but heat treatment gives ordered structures, which are thought to be reconstructed GaP(001) structures induced by Cs. The LEED patterns showed the GaP(001)(1 × 2) Cs structure formed at 180°C for 10 h with a Cs coverage of 5 × 1014 atoms cm?2, the GaP(001)(1 × 4) Cs formed at 210°C for 10 hours with a Cs coverage of 2.7 × 1014 atoms cm?2, the GaP(001)(7 × 1) and the high temperature GaP(001)(1 × 4), the latter two with very low Cs content. Desorption measurements show three stability regions: (a) between 25–150°C for coverages greater than 5 × 1014 atoms cm?2, and an activation energy of 1.2 eV; (b) between 180–200°C with a coverage of 5 × 1014 atoms cm?2, and an activation energy of 1.8 eV; (c) between 210–400°C with a coverage of 2.7 × 1014 atoms cm?2, and an activation energy of 2.5 eV. 相似文献
16.
M. Saglam A. Türüt Ç. Nuhoglu H. Efeoglu T. Kılıçoglu M.A. Ebeoglu 《Applied Physics A: Materials Science & Processing》1997,65(1):33-37
2 /p-Si MOS structures were prepared in 0.1 M K2SO4 electrolyte with a pH of 7 (the 0.1 M KOH solution was buffered with H2SO4) at current densities of 3, 5, and 7 mA/cm2 and with four different pH values of the electrolyte at 3 mA/cm2. It is found that thermal annealing at a relatively low temperature can be used to improve the anodic MOS characteristics.
Moreover, of the pH and current density it followed that the pH has a dominant role in the interface electrical properties.
The lowest interface state densities at the maximum and the midgap positions are 7.1×1011 and 2.7×1010 eV-1cm-2 for a sample made with pH=7, J=3 mA/cm2. The characteristics of this sample seem satisfactory for device applications of anodized p-Si.
Received: 8 July 1996/Accepted: 22 January 1997 相似文献
17.
We present in this work a new experimental set-up for sensitive detection of reactive species: continuous wave cavity ring-down spectroscopy (cw-CRDS) as a detection method in laser photolysis reactor. HO2 radicals were generated by using a 248 nm photolysis of SOCl2/CH3OH/O2 mixtures and were detected in the first vibrational overtone of the OH stretch around 6625 cm-1, using a DFB diode laser. In order to perform the spectroscopic and kinetic measurements of the HO2 radical, two different timing schemes have been used. The absorption line strength of the transition at 6625.784 cm-1 has been extracted from kinetic measurement to (5.2±1.0)×10-21 cm2 molecule-1cm-1. The detection limit for the actual set-up is 2×1012 molecules cm-3. PACS 42.62.Fi; 82.33.Tb; 82.20.W 相似文献
18.
T. Sameshima Y. Kaneko N. Andoh 《Applied Physics A: Materials Science & Processing》2001,73(4):419-423
50-nm thick amorphous silicon films formed on glass substrates were crystallized by rapid Joule heating induced by an electrical
current flowing in 100-nm-thick Cr strips formed adjacently to 200-nm-thick SiO2 intermediate layers. 3-μs-pulsed voltages were applied to the Cr strips. Melting of the Cr strips caused a high Joule heating
intensity of about 1×106 W/cm2. Raman scattering measurements revealed complete crystallization of the silicon films at a Joule heating energy of 1.9 J/cm2 via the SiO2 intermediate layer. Transmission electron microscopy measurements confirmed a crystalline grain size of 50–100 nm. 1-μm-long
crystalline grain growth was also observed just beneath the edge of the Cr strips. The electrical conductivity increased from
10-5 S/cm to 0.3 S/cm for 7×1017-cm-3-phosphorus-doped silicon films because of activation of the phosphorus atoms because of crystallization. The numerical analysis
showed a density of localized defect states at the mid gap of 8.0×1017 cm-3. Oxygen plasma treatment at 250 °C and 100 W for 5 min reduced the density of the defect states to 2.7×1017 cm-3.
Received: 3 April 2001 / Accepted: 9 April 2001 / Published online: 25 July 2001 相似文献
19.
O. Silvestre M.C. Pujol M. Rico F. Güell M. Aguiló F. Díaz 《Applied physics. B, Lasers and optics》2007,87(4):707-716
This paper presents the crystal growth and optical characterization of thulium-doped KLu(WO4)2 (KLuW). Thulium-doped KLuW macrodefect-free monoclinic single crystals (a*×b×c≈10×7×15 mm3) were grown by the top seeded solution growth slow cooling method with dopant concentrations of 0.5%, 1%, 3% and 5% atomic
in solution. The evolution of unit cell parameters in relation with thulium doping was studied by X-ray powder patterns. Thulium
energy levels in the KLuW host were determined by 6 K polarized optical absorption. The Judd–Ofelt parameters determined were
Ω2=9.01×10-20 cm2, Ω4=1.36×10-20 cm2 and Ω6=1.43×10-20 cm2. The maximum emission cross section for the 1.9 μm emission, calculated by Füchtbauer–Ladenburg method, is 1.75×10-20 cm2, at 1845 nm with E//Nm. The intensity decay time from the emitting levels 1
G
4 and 3
H
4 levels in relation to the concentration were studied. For the lowest thulium concentration, the measured decay times from
1
G
4 and 3
H
4 emitting levels are 140 μs and 230 μs, respectively.
PACS 42.55.Rz; 78.20.-e; 78.55.-m 相似文献