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881.
The gas-phase ion chemistry of silane-allene-ammonia, germane-allene (or propyne)-ammonia (or phosphine) systems was studied by ion trap mass spectrometry. Reaction sequences were determined and rate constants were measured for the main processes observed. The mixture containing silane displays higher reactivity with respect to that with germane. Comparison with analogous systems provides useful information about the reactivity of different hydrocarbon molecules and the different affinities of silicon and germanium towards nitrogen and phosphorus. The most interesting product ions observed are those containing Si (or Ge), C and N (or P) elements together, as these ion species may be considered precursors of doped amorphous carbides, which are widely used in semiconductor devices. 相似文献
882.
Preparation and characterization of room-temperature ferromagnetism GaMnN based on ion implantation 总被引:1,自引:0,他引:1
This paper reports the fabrication of GaMnN ferromagnetic semiconductor on GaN substrate by high-dose Mn ion implantation. Both the structural and optical properties for Mn+-implanted GaN material were studied by X-ray diffraction, Raman scattering and photolumi-nescence. The results reveal that the implanted manganese incorporates on Ga site and GaMnN ternary phase is formed in the substrate. The magnetic behavior has been characterized by superconducting quantum interference device. The material shows room-temperature ferromagnet-ism. The temperature-dependent magnetization indicates different mechanism for ferromagnetism in Mn+-implanted GaN. 相似文献
883.
B. F. Kuntsevich A. A. Mel'nikov V. K. Kononenko 《Journal of Applied Spectroscopy》2003,70(2):285-291
The influence of tuning the lasing monochromatic radiation frequency g within the amplification band on the nonlinear response of the semiconductor laser with harmonic modulation of pump current is investigated theoretically. It is established that the principal features of the behavior of the nonlinear amplitude-detuning characteristic (ADC) are determined by the relation between the current modulation frequency m and the main resonance frequency of the laser r. If m r, then with increase in g the response decreases monotonically mainly due to the decrease of its dynamic component. The exception is provided by the spectral regions where peaks on the ADC appear because of the explicitly nonlinear lasing regimes (period doubling, chaos, etc.) When m < r, the resonance conditions for induced oscillations are satisfied only for definite spectral intervals within the amplification band and a dip appears on the low-frequency side of the ADC. With decreasing m, the dip boundary shifts to a more high-frequency region of the band corresponding to smaller local resonance frequencies. The peaks on the ADC corresponding to the radiation period doubling shift to the region of smaller values of g on increase in m. 相似文献
884.
K. Allakhverdiev J. Goldstein N. Fernelius D. Huseinova E. Salaev A. Türker 《International Journal of Infrared and Millimeter Waves》2005,26(3):457-466
We report the measurement of the temperature dependence of the absorption spectra of - GaSe over the temperature range 300 K to 5 K. Measurements have been made for both the e-ray (polarized parallel to the crystals c-axis) and the o-ray (polarized perpendicular to the c-axis), over the spectral range 4000 to 10 cm–1. Nine absorption lines at 417, 440, 499, 546, 891, 945, 1015, 1093, 1270 cm–1 were recorded at 300 K for the e- ray spectra. Some of these lines were identified using the results of a modified single layer, linear chain model of GaSe. The lines at 417, 440 and 499 cm–1 were assigned to local impurity absorption originating from N, Mg and O, respectively. The weak lines at 945, 1015 and 1093 cm–1 were assigned to hole transitions from the acceptor levels to the top of the valence band. Two absorption lines at 891 cm–1 and 1270 cm–1 were assigned to hole transitions from the quasi-local acceptor levels to the double degenerate valence sub-bands 5 or 6. The origin of lines recorded in the far IR absorption spectra at 20, 37 cm–1 and 362 cm–1 were also identified. 相似文献
885.
B.?F.?Kuntsevich A.?N.?PisarchikEmail author V.?K.?Kononenko 《Optical and Quantum Electronics》2005,37(7):675-693
A detailed numerical study of dynamical behavior of a semiconductor laser under current modulation and cavity detuning has been performed on the base of four different models of the active medium which take into account direct transitions between ground subbands, transitions with no k-selection rule between ground subbands and contribution of excited subbands in each of the above-mentioned cases. We have shown that different nonlinear regimes (period doubling, chaos, generalized bistability) can be obtained either with cavity detuning from the gain band maximum or near the laser threshold.It has been established that the shape and principal peculiarities of amplitude detuning characteristics are determined by the relation between the current modulation frequency and maximum resonance frequency of the laser.PACS numbers: 05.45.Pq, 42.55.Px, 42.65.Sf 相似文献
886.
Jianji?Dong Xinliang?ZhangEmail author Zhong?Jiang Dexiu?Luang 《Optical and Quantum Electronics》2005,37(11):1011-1023
We analyze the all-optical wavelength converter (AOWC)-based on cross-gain modulation (XGM) in a single-port-coupled (SPC)
semiconductor optical amplifier (SOA). A comprehensive dynamic model is developed by considering longitudinal variations of
the carrier density, the residual rear-facet reflectivity of the SOA and the wide-band spontaneous noise emission. The numerical
simulations for the novel wavelength conversion at 10 Gbit/s are presented based on the model. The extinction ratio (ER),
conversion efficiency and pattern effect of the SPC-SOA-based wavelength converters are investigated, respectively. Compared
with the traditional scheme of the double-portcoupled (DPC) SOA, the SPC-SOA scheme has better performance. We have obtained
that the ER is higher than 10 dB with the pump wavelength turned over 15nm from experiments. The experimental results are
in agreement with the simulation results. 相似文献
887.
Far infrared reflection and Raman spectra of InSe were measured at 5, 77 and 300 K. Phonon frequencies obtained by reflection spectra were well explained by two-point phonon combination. The crystal structure of-type was confirmed at low temperature. Ion blocking analysis supported also no change of phase by temperature in this semiconductor. 相似文献
888.
Stroyuk A. L. Raevskaya A. E. Kuchmii S. Ya. 《Theoretical and Experimental Chemistry》2004,40(2):130-135
We have studied the photochemical behavior of colloidal solutions of cadmium sulfide containing polysulfide ions under pulsed irradiation conditions. We have established that the pulsed photolysis product responsible for absorption in the 520-650 nm region is the radical anion S
3
. We have studied the kinetic characteristics of disappearance of this intermediate under various conditions, and we propose a scheme for the mechanism of these processes. 相似文献
889.
Raffaele Luigi De La Rue Richard M. Krauss Thomas F. 《Optical and Quantum Electronics》2002,34(1-3):101-111
We present very compact, as short as 20 m long, low-threshold in-plane semiconductor lasers operating at a wavelength of 980 nm, in which microstructured mirrors have been formed at both cavity ends by deep reactive ion etching (RIE). The back mirror consists of a seven-period third order Bragg reflector with a measured reflectivity of 95%. The front mirror has a similar configuration, but consists of three periods with a lower reflectivity (80%) in order to allow output coupling. Lasing has been achieved from 20 m long and 8 m wide devices exhibiting a current threshold of 7 mA. These are among the shortest in-plane Fabry–Perot electrically pumped lasers demonstrated to date. Design issues are discussed, along with experimental data from which values for the reflectivity of the mirrors are derived. State-of-the-art electron beam lithography (EBL) and high-aspect-ratio RIE have been used for device fabrication, while additional strategies are proposed for the further improvement of the device performance. 相似文献
890.
The statistic properties of photon emissions from single
semiconductor quantum dots with V-type level driven by pulses are
investigated theoretically. Based on quantum regression theorem and master
equations, the dynamic equations of the second-order correlation function of
the photon emissions are deduced. The calculated results reveal that the
efficiency of single photon emissions from two orthogonal polarization
eigenstates |x〉and
|y〉) reaches the maximum
when the input pulses area is about π, and the probability of the
cross-polarized single photon emission from |x 〉 and
|y 〉decreases with increasing of pulse width. 相似文献