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1.
Power optimization of small-scale chemical oxygen-iodine laser withjet-type singlet oxygen generator
Blayvas I. Barmashenko B.D. Furman D. Rosenwaks S. Zagidullin M.V. 《Quantum Electronics, IEEE Journal of》1996,32(12):2051-2057
Studies of power optimization of a 5-cm gain length chemical oxygen-iodine laser (COIL) energized by a jet-type singlet oxygen generator (JSOG) are presented. For 10 mmol/s of Cl2 flow rate, output power of 132 W with chemical efficiency of 14.5% was obtained without a water vapor trap, 163 W and 18% were achieved when coholed (173 K). He was introduced downstream of the JSOG; under these conditions, the small-signal gain was estimated to be 0.32% cm-1 . 190 W and 10.5% were obtained for 20 mmol/s of CI2 flow rate. Replacing He by N2 as a buffer gas resulted in a 13% power decrease only. The main key for increasing the chemical efficiency of a COIL without a water vapor trap for a given iodine-oxygen mixing system is found to be high oxygen pressure and low water vapor pressure inside the reaction zone of the JSOG. The last goal was achieved by optimizing the composition and temperature of the basic hydrogen-peroxide solution (BHP). The experimental results are discussed and related to the composition and flow conditions of the gaseous reactants and of the BHP 相似文献
2.
Wani F. Endo M. Vyskubenko B.A. Ilyin S.P. Krukovsky I.M. Takeda S. Fujioka T. 《Quantum Electronics, IEEE Journal of》1998,34(11):2130-2137
A twisted aerosol singlet oxygen generator (TA-SOG), which is a new high-pressure SOG for the supersonic chemical oxygen-iodine laser (COIL), was developed. Its operational characteristics were compared to those of a conventional liquid-jet-type singlet oxygen generator. It was shown that TA-SOG is operated at an internal gas velocity of 85 m/s, which is three times higher than that of the jet-type SOG. Cl2 utilization of 70% and singlet oxygen O2 (1Δ) yield of 85% were obtained under this condition. The results of our two-dimensional model calculation suggested that there must be some enhancement of a specific surface area in the reaction zone. The mechanism of this effect is discussed 相似文献
3.
Knickelbein M.B. Marsh K.L. Sercel J. Siebert L.D. Busch G.E. 《Quantum Electronics, IEEE Journal of》1988,24(7):1278-1288
Simple kinetics calculations demonstrate that the well-known electronic energy pooling reaction involving O2(a 1Δ) is capable of producing an effective population inversion in O2(b 1Σ). The densities of O2(a 1Δ) which are potentially achievable suggest that the extractable energy storage density of an O 2(b →X ) chemical laser might exceed 0.5 MJ/m3. The b →X emission lifetime measurements conducted under conditions of high relative O2( b 1Σ) density reveal no evidence of rapid self-quenching effects which would be potentially detrimental to laser performance. The relatively long energy storage times predicted, together with freedom from reagent mixing requirements, make such a laser an attractive alternative to other existing and proposed short wavelength chemical lasers 相似文献
4.
Furman D. Bruins E. Rybalkin V. Barmashenko B.D. Rosenwaks S. 《Quantum Electronics, IEEE Journal of》2001,37(2):174-182
A detailed experimental study of the gain and temperature in the cavity of a supersonic chemical oxygen-iodine laser (COIL) is carried out to find optimal values of the flow parameters corresponding to the maximum gain. It is found that high gain (>0.7%/cm) can be obtained in a COIL operating without primary buffer gas and, hence, having a high gas temperature (>250 K) in the cavity. The measurements are performed for slit nozzles with different numbers and positions of iodine injection holes. Using a diode laser-based diagnostic, the gain is studied as a function of the molar flow rates of various reagents, with optical axis position along and across the flow, and Mach number in the cavity. Maximum gain of 0.73%/cm is obtained at chlorine and secondary nitrogen flow rates of 15 mmole/s and 7 mmole/s, respectively, for a slit nozzle with transonic injection of iodine. The gain is found to be strongly inhomogeneous across the flow. For a slit nozzle with iodine injection in the diverging part of the nozzle, the values of the maximum gain are smaller than for nozzles with transonic injection. Opening a leak downstream of the cavity in order to decrease the Mach number and increase the cavity pressure results in a decrease of the gain and dissociation fraction. The gain is a nonmonotonic function of the iodine flow rate, whereas the temperature increases with increasing iodine flow. An analytical model is developed for calculating in slit nozzles the iodine dissociation fraction F and the number N of O2 (1Δ) molecules lost in the region of iodine dissociation per I2 molecule 相似文献
5.
Horng Nan Chern Chung Len Lee Tan Fu Lei 《Electron Device Letters, IEEE》1993,14(3):115-117
It is reported for that H2 plasma followed by O2 plasma is more effective for passivating grain boundary states in polysilicon thin film. Polysilicon thin-film transistors (TFTs) made after H2/O2 plasma treatment can exhibit a turn-on threshold voltage of -0.1 V, a subthreshold swing of 0.154 V/decade, an ON/OFF current ratio I on/I off over 1×108, and an electron mobility of 40.2 cm2 /V-s 相似文献
6.
7.
The small signal gain coefficients were measured in Tm3+,Ho3+ co-doped alumino-zirco-fluoride glass. A gain of 15%/cm at 2.05 μm was obtained for pump power density of 42 kW/cm2. The temperature increase of the glass was found to be more than 150 K with this pump power, which was estimated from a comparison between fluorescence intensities of Tm3+ 3 F4-3H6 and Ho3+ 5 I7-5I8. An upconversion rate constant of 12.5×10-17 cm3 sec-1 from a coupled (Tm3+ 3F4, Ho3+ 5I7) level to a coupled (Tm3+ 3H5, Ho3+ 5I6) level was determined by fitting the experimentally obtained gain coefficients to the calculated one which takes into consideration any temperature increase 相似文献
8.
N-channel metal oxide semiconductor field effect transistors (MOSFETs) using Ta2O5, gate oxide were fabricated. The Ta2O5 films were deposited by plasma enhanced chemical vapor deposition. The IDS-VDS and IDS-VGS characteristics mere measured. The electron mobility was 333 cm2/V·s. The subthreshold swing was 73 mV/dec. The interface trapped charge density, the surface recombination velocity, and the minority carrier lifetime in the field-induced depletion region measured from gated diodes were 9.5×1012 cm-2 eV-1, 780 cm/s and 3×10-6 sec, respectively. A comparison with conventional MOSFETs using SiO2 gate oxide was made 相似文献
9.
An In0.41Al0.59As/n+-In0.65 Ga0.35As HFET on InP was designed and fabricated, using the following methodology to enhance device breakdown: a quantum-well channel to introduce electron quantization and increase the effective channel bandgap, a strained In0.41Al0.59As insulator, and the elimination of parasitic mesa-sidewall gate leakage. The In0.65Ga0.35As channel is optimally doped to N D=6×1018 cm-3. The resulting device (L g=1.9 μm, W g =200 μm) has f t=14.9 GHz, f max in the range of 85 to 101 GHz, MSG=17.6 dB at 12 GHz V B=12.8 V, and I D(max)=302 mA/mm. This structure offers the promise of high-voltage applications at high frequencies on InP 相似文献
10.
The first application of a new technique (SiH4+O2 at 83-330°C and 2-12 torr) for deposition of SiO2 on InP is reported. SiO2 deposited at 150-330°C has breakdown strength of 8-10 MV/cm, resistivity >1015 Ωcm, and refractive index of 1.45-1.46 comparable to thermal SiO 2 grown at 1100°C. C /V measurements on Al/SiO2/InP MIS structures suggest that very low temperature oxides (90-100°C) have the best interfacial properties 相似文献
11.
A new post-metallization annealing technique was developed to improve the quality of metal-oxide-semiconductor (MOS) devices using SiO 2 films formed by a parallel-plate remote plasma chemical vapor deposition as gate insulators. The quality of the interface between SiO2 and crystalline Si was investigated by capacitance-voltage (C-V) measurements. An H2O vapor annealing at 270°C for 30 min efficiently decreased the interface trap density to 2.0×1010 cm-2 eV-1, and the effective oxide charge density from 1×10 12 to 5×109 cm-2. This annealing process was also applied to the fabrication of Al-gate polycrystalline silicon thin film transistors (poly-Si TFT's) at 270°C. In p-channel poly-Si TFT's, the carrier mobility increased from 60-400 cm2 V-1 s-1 and the threshold voltage decreased from -5.5 to -1.7 V 相似文献
12.
Riley P.E. Defonseka B.N. Sum J.C. Figueredo D. 《Semiconductor Manufacturing, IEEE Transactions on》1993,6(3):290-292
A plasma etching process for patterning LPCVD (low-pressure chemical vapor deposition) Si3N4 which has been formed on thin thermally grown SiO2 has been developed and characterized with an Applied Materials 8110 batch system using 100-mm-diameter silicon wafers. To fulfill the primary process objectives of minimal critical dimension (CD) loss (~0.08 μm), vertical profiles after etch, retention of some of the underlying thermal SiO2, and batch etch uniformity, the reactor has been characterized by evaluating the effects of variation of reactor pressure (15 to 65 mTorr), O2 concentration by flow rate (30 to 70%) of an O2/CHF2 mixture, and DC bias voltage (-200 to -550 V). Analysis of the resulting etch rate, etch uniformity, dimensional, and profile data suggests that satisfactory processing may be achieved at low reactor pressure (~25 mTorr), 50-60% O2 by flow rate in O2/CHF3, and low DC bias (-200 to -250 V) 相似文献
13.
Pujol M.C. Massons J. Aguilo M. Diaz F. Rico M. Zaldo C. 《Quantum Electronics, IEEE Journal of》2002,38(1):93-100
The spectroscopic properties of Ho3+ laser channels in KGd(WO4)2 crystals have been investigated using optical absorption, photoluminescence, and lifetime measurements. The radiative lifetimes of Ho3+ have been calculated through a Judd-Ofelt (JO) formalism using 300-K optical absorption results. The JO parameters obtained were Ω2=15.35×10-20 cm2, Ω 4=3.79×10-20 cm2, Ω6 =1.69×10-20 cm2. The 7-300-K lifetimes obtained in diluted (8·1018 cm-3) KGW:0.1% Ho samples are: τ(5F3)≈0.9 μs, τ( 5S2)=19-3.6 μs, and τ(5F5 )≈1.1 μs. For Ho concentrations below 1.5×1020 cm-3, multiphonon emission is the main source of non radiative losses, and the temperature independent multiphonon probability in KGW is found to follow the energy gap law τph -1(0)=βexp(-αΔE), where β=1.4×10-7 s-1, and α=1.4×103 cm. Above this holmium concentration, energy transfer between Ho impurities also contributes to the losses. The spectral distributions of the Ho3+ emission cross section σEM for several laser channels are calculated in σ- and π-polarized configurations. The peak a σEM values achieved for transitions to the 5I8 level are ≈2×10-20 cm2 in the σ-polarized configuration, and three main lasing peaks at 2.02, 2.05, and 2.07 μm are envisaged inside the 5I7→5I8 channel 相似文献
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15.
Benjie Fang Fang Chen Yuelong Zhang Fengting Sang Yuqi Jin Zengqiang Wang Qingwei Li 《Quantum Electronics, IEEE Journal of》2003,39(12):1619-1624
A 2-kW-class chemical oxygen-iodine laser (COIL) using nitrogen buffer gas has been developed and tested since industrial applications of COIL devices will require the use of nitrogen as the buffer gas. The laser, with a gain length of 11.7 cm, is energized by a square pipe-array jet-type singlet oxygen generator (SPJSOG) and employs a nozzle bank with a designed Mach number of 2.5. The SPJSOG has advantages over the traditional plate-type JSOG in that it has less requirements on basic hydrogen peroxide (BHP) pump, and more important, it has much better operational stability. The SPJSOG without a cold trap and a gas-liquid separator could provide reliable operations for a total gas flow rate up to 450 mmol/s and with a low liquid driving pressure of around 0.7 atm or even lower. The nozzle bank was specially designed for a COIL using nitrogen as the buffer gas. The cavity was designed for a Mach number of 2.5, in order to provide a gas speed and static temperature in the cavity similar to that for a traditional COIL with helium buffer gas and a Mach 2 nozzle. An output power of 2.6 kW was obtained for a chlorine flow rate of 140 mmol/s, corresponding to a chemical efficiency of 20.4%. When the chlorine flow rate was reduced to 115 mmol/s, a higher chemical efficiency of 22.7% was attained. Measurements showed that the SPJSOG during normal operation could provide a singlet oxygen yield Y/spl ges/55%, a chlorine utilization U/spl ges/85%, and a relative water vapor concentration w=[H/sub 2/O]/([O/sub 2/]+[Cl/sub 2/])/spl les/0.1. 相似文献
16.
Lo G.Q. Kwong D.-L. Fazan P.C. Mathews V.K. Sandler N. 《Electron Device Letters, IEEE》1993,14(5):216-218
The authors report on a highly reliable stacked storage capacitor with ultrahigh capacitance using rapid-thermal-annealed low-pressure chemical vapor deposited (LPCVD) Ta2O5 films (~100 Å) deposited on NH3-nitrided rugged poly-Si electrodes. Capacitances as high as 20.4 fF/μ2 (corresponding to the thinnest t ox.eff (16.9 Å) ever reported using LPCVD-Ta2O5 and poly-Si technologies) have been achieved with excellent leakage current and time-dependent dielectric breakdown (TDDB) characteristics. Extensive electrical characterization over a wide temperature range (~25-300°C) shows that Ta2O 5 films on rugged poly-Si electrodes have a better temperature stability in dielectric leakage and breakdown compared to the films on smooth poly-Si electrodes 相似文献
17.
Vassilevski K.V. Zekentes K. Zorenko A.V. Romanov L.P. 《Electron Device Letters, IEEE》2000,21(10):485-487
4H-SiC p+-n-n+ diodes of low series resistivity (<1×10-4 Ω·cm2) were fabricated and packaged. The diodes exhibited homogeneous avalanche breakdown at voltages Ub=250-270 V according to the doping level of the n layer. The temperature coefficient of the breakdown voltage was measured to be 2.6×10-4 k-1 in the temperature range 300 to 573 K. These diodes were capable of dissipating a pulsed power density of 3.7 MW/cm2 under avalanche current conditions. The transient thermal resistance of the diode was measured to be 0.6 K/W for a 100-ns pulse width, An experimental determination of the electron saturated drift velocity along the c-axis in 4H-SIC was performed for the first time, It was estimated to be 0.8×107 cm/s at room temperature and 0.75×107 cm/s at approximately 360 K 相似文献
18.
Che-Chung Chou Evenson K.M. Zink K.R. Maki A.G. Jow-Tsong Shy 《Quantum Electronics, IEEE Journal of》1995,31(2):343-345
Nineteen new laser lines in the 11-μm wavelength region have been observed in CW oscillation from a CO2 laser with a high-Q, high-resolution cavity at a higher than usual current density. The frequency of each line has been measured using heterodyne frequency measurement techniques. Analysis of the frequencies shows that 15 lines are rotation-vibration transitions of the 0112-[1111,0311]I band (the first sequence hot band) of the CO2 molecule and four lines belong to the rotation-vibration transitions of the 0221-[12 20, 0420]I band of CO2 相似文献
19.
King C.A. Hoyt J.L. Gronet C.M. Gibbons J.F. Scott M. Turner J. 《Electron Device Letters, IEEE》1989,10(2):52-54
Si/Si1-xGex heterojunction transistors (HBTs) fabricated by a chemical vapor deposition (CVD) technique are reported. A rapid thermal CVD limited-reaction processing (LRP) technique was used for the in situ growth of all three device layers, including a 20-mm Si1-xGex layer in the base. The highest current gains observed (β=400) were for a Si/Si1-x Gex HBT with a base doping of 7×1018 cm-3 near the junction and a shallow arsenic implant to form ohmic contacts and increase current gain. Ideal base currents were observed for over six decades of current and the collector current remained ideal for nearly nine current decades starting at 1 pA. The bandgap difference between a p-type Si layer doped to 5×1017 cm-3 and the Si1-xGex(x=0.31) base measured 0.27 eV. This value was deduced from the measurements of the temperature dependence of the base current and is in good agreement with published calculations for strained Si1-xGex layers on Si 相似文献
20.
原子层沉积(ALD)方法可以制备出高质量薄膜,被认为是可应用于柔性有机电致发光器件(OLED)最有发展前景的薄膜封装技术之一。本文采用原子层沉积(ALD)技术,在低温(80℃)下,研究了Al2O3及TiO2薄膜的生长规律,通过钙膜水汽透过率(WVTR)、薄膜接触角测试等手段,研究了不同堆叠结构的多层Al2O3/TiO2复合封装薄膜的水汽阻隔特性,其中5 nm/5 nm×8 dyads(重复堆叠次数)的Al2O3/TiO2叠层结构薄膜的WVTR达到2.1×10-5 g/m2/day。采用优化后的Al2O3/TiO2叠层结构薄膜对OLED器件进行封装,实验发现封装后的OLED器件在高温高湿条件下展现了较好的寿命特性。 相似文献