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用单次脉冲非稳腔空间增强探测CARS技术测量火焰温度 总被引:6,自引:0,他引:6
采用宽带相干反斯托克斯拉曼散射(CARS)技术测量了甲烷-空气预混火焰温度场分布,并分析了温度测量的不确定度.建立的宽带CARS实验系统采用非稳腔空间增强探测(USED)相位匹配构造,其横向空间分辨率约0.1 mm,纵向空间分辨率约3 mm,该系统能实现10 Hz重复频率测量火焰瞬时温度.采用宽带非稳腔空间增强探测CARS在甲烷-空气预混火焰中获得了单次激光脉冲的高信噪比氮气Q支CARS实验谱,用CARS理论计算软件拟合理论谱和实验谱确定了预混火焰的温度随高度的分布,采用单次激光脉冲的氮气Q支CARS实验谱测量火焰温度的不确定度小于5%. 相似文献
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同时测量氢和氧CARS谱的新方法 总被引:1,自引:0,他引:1
提出一种仅需一台染料激光器即可同时测量火焰中氢和氧的CARS谱的新方法.取带宽为120cm~(-1).中心波长位于580.4nm的Stokes光束与532nm的泵浦光束相配合.同时测量氢扩散火焰中的氢和氧的CARS谱.用氢的S(6)和S(5)的积分强度比确定火焰中的温度并与氮的Q支CARS谱测量的温度和经过热损耗修正的热电偶测得的温度取得了相当好的一致结果.一次测出氢和氧的CARS谱.避免多次测量中参数的难以重复性.提高了以温度为参数来确定浓度的准确性. 相似文献
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Tantalum pentoxide (Ta2O5) deposited by pulsed DC magnetron sputtering technique as the gate dielectric for 4H-SiC based metal-insulator-semiconductor (MIS) structure has been investigated. A rectifying current-voltage characteristic was observed, with the injection of current occurred when a positive DC bias was applied to the gate electrode with respect to the n type 4H-SiC substrate. This undesirable behavior is attributed to the relatively small band gap of Ta2O5 of around 4.3 eV, resulting in a small band offset between the 4H-SiC and Ta2O5. To overcome this problem, a thin thermal silicon oxide layer was introduced between Ta2O5 and 4H-SiC. This has substantially reduced the leakage current through the MIS structure. Further improvement was obtained by annealing the Ta2O5 at 900 °C in oxygen. The annealing has also reduced the effective charge in the dielectric film, as deduced from high frequency C-V measurements of the Ta2O5/SiO2/4H-SiC capacitors. 相似文献
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N. M. Abdullayev S. I. Mekhtiyeva N. R. Memmedov M. A. Ramazanov A. M. Kerimova 《Semiconductors》2010,44(6):824-827
The crystallization dynamics of Bi2Te3-Bi2Se3 polycrystalline films annealed at 200–230°C has been investigated. The formation of ordered blocks 70—150 nm in size, depending
on the annealing time and temperature, is observed. 相似文献
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Fluorescence enhancement of red and blue concurrently emitting Ba3MgSi2O8:Eu2+,Mn2+ phosphors for plant cultivation has been investigated by Dy3+ addition. The Ba3MgSi2O8:Eu2+,Mn2+,Dy3+(BMS-EMD) phosphors have two-color emissions at the wavelength peak values of 437 nm and 620 nm at the excitation of 350 nm.
The two emission bands are coincident with the absorption spectrum for photosynthesis of plants. An obvious enhancement effect
has been observed upon addition of Dy3+ with amount of 0.03 mol%, in which the intensities of both blue and red bands reach a maximum. The origin of red and blue
emission bands is analysed. The photochromic parameters of the samples at the nearly UV excitation are tested. This fluoresence
enhancement is of great significance for special solid state lighting equipment used in plant cultivation.
This work has been supported by National Natural Science Foundation of China (Grant No 50872091) and the Natural Science Foundation
of Tianjin, China (06YFJMJC02300, 06TXTJJC14602). 相似文献
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D. Zade S. Sato A. Srivastava K. Tsutsui N. Sugii T. Hattori H. Iwai 《Microelectronics Reliability》2011,51(4):746-750
The effect of La2O3 incorporation on the spatial trap distribution in HfO2 gate dielectrics is investigated. The incorporation of La2O3 in HfO2 dielectric has been found to improve the effective mobility in addition to reduced interface-state density. The trap distribution analysis in the HfO2 layer extracted by combining the charge pumping (CP) method and the low-frequency noise (LFN) method has revealed significant reduction in the amount of traps at HfO2/SiO2-interlayer interface and in the HfO2 layer by La2O3 incorporation. 相似文献
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The trapping/detrapping behavior of charge carriers in ultrathin SiO2/TiO2 stacked gate dielectric during constant current (CCS) and voltage stressing (CVS) has been investigated. Titanium tetrakis iso-propoxides (TTIP) was used as the organometallic source for the deposition of ultra-thin TiO2 films at low temperature (<200 °C) on strained-Si/relaxed-Si0.8Ge0.2 heterolayers by plasma-enhanced chemical vapor deposition (PECVD) in a microwave (700 W, 2.45 GHz) plasma cavity discharge system at a pressure of 66.67 Pa. Stress-induced leakage current (SILC) through SiO2/TiO2 stacked gate dielectric is modeled by taking into account the inelastic trap-assisted tunneling (ITAT) mechanism via traps located below the conduction band of TiO2 layer. The increase in the gate current density observed during CVS from room temperature up to 125 oC has been analyzed and modeled considering both the buildup of charges in the layer as well as the SILC contribution. Trap generation rate and trap cross-section are extracted. A capture cross-section in the range of 10−19 cm2 as compared to 10−16 cm2 in SiO2 has been observed. A temperature-dependent trap generation rate and defects have also been investigated using time-dependent current density variation during CVS. The time dependence of defect density variation is calculated within the dispersive transport model, assuming that these defects are produced during random hopping transport of positively charge species in the insulating high-k stacked layers. SILC generation kinetics, i.e. defect generation probability under different injected fluences for various high-constant stress voltages in both polarities have been studied. An empirical relation between trap generation probability and applied stress voltage for various injected fluences has been developed. 相似文献
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Isodiana Crupi Robin Degraeve Bogdan Govoreanu David P. Brunco Philippe Roussel Jan Van Houdt 《Microelectronics Reliability》2007,47(4-5):525
In this work we combine charge-pumping measurements with positive constant voltage stress to investigate trap generation in SiO2/Al2O3 n-MOSFET. Trap density has been scanned either in energy or in position based on charge-pumping (CP) measurements performed under different operating conditions in terms of amplitude and frequency of the gate pulse. Our results have revealed that the traps are meanly localized shallow in energy level, deeper in spatial position and they are mostly generated near the Si/SiO2 interface. 相似文献
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室温下利用337nm脉冲激光照射着色LiF晶体,有效地将F2心转变成F2+心,其浓度高于1016cm-3。利用消象散三镜折叠腔,研究了LiF晶体F2和F2+心激光特性。实际工作表明,利用氮分子激光作为处理光束,可获得较长时间稳定的F2+心激光输出。 相似文献
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Isodiana Crupi Robin Degraeve Bogdan Govoreanu David P. Brunco Philippe Roussel Jan Van Houdt 《Materials Science in Semiconductor Processing》2006,9(6):889
In this paper, we present our results on the distribution and generation of traps in a SiO2/Al2O3 transistor. The investigation has been carried out by using charge pumping measurements, both variable voltage and frequency techniques, and constant voltage stress.By increasing the amplitude of the gate pulse we observe an increase of the charge recombined per cycle closely related to the contribution of shallow traps near the SiO2/Al2O3 interface. By reducing the pulse frequency we measure an increase in the charge pumping current due to traps located deeper in the Al2O3. By combining charge pumping and constant voltage stress measurements, we found that the traps are mostly generated near the Si/SiO2 interface. 相似文献
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The impact of various rapid thermal annealing used during the integration on the La2O3/HfO2 and HfO2/La2O3 stacks deposited by Atomic Layer deposition was analyzed. The consequences of lanthanum localization in such stacks on the evolution of the films during the rapid thermal annealing are investigated in term of morphology, crystalline structure, silicate formation and film homogeneity as a function of the depth. It appeared that the La2O3 location has an impact on the temperature of the quadratic phase formation which could be linked to the formation of SiOHfLa silicate and the resistance of the films to dissolution in HF 0.05 wt%. 相似文献