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71.
The growth of liquid phase epitaxial (LPE) layers of n-type GaP on GaP substrates was investigated using a multi-wafer growth
system constructed of fused quartz which had provisions for gas phase saturation and doping of the gallium melt. The effect
of growth temperature, substrate orientation, doping level, and repeated use of the same melt on the properties of zinc diffused
electroluminescent diodes fabricated from these epitaxial layers were investigated. After an initial increase, the carrier
concentration remained relatively constant (1.7 × 1017/cc) throughout a series of eighteen runs from the same melt. Using conventional commercial techniques, zinc diffused diodes
with efficiencies of 0.05% at 30A/cm2 and a brightness of 1200 fL at 10A/cm2 were produced. These diodes had a limited area n and p-type contact and had an epoxy dome. Layers grown on the 〈 111 〉P orientation
had the best surface quality whereas those grown on the 〈 100 〉 plane incorporated less background impurities. The use of
relatively low growth starting temperatures (∼ 920°C) was found to minimize the background impurity of the layers and the
substrate surface deterioration due to the reaction with ammonia.
This work was, in part, sponsored by the Air Force Materials Laboratory under the direction of Mrs. E. H. Tarrants, contract
number F33615-71-C-1621 相似文献
72.
A combination of optical microscopy and transmission electron microscopy has been used to provide direct evidence that pits
formed by the action of a solution of 3 HF:1 H2O2 on epitaxial and substrate GaP material close to the (001 ) orientation are associated with dislocations. The formation of
different pit shapes can be correlated with previous work on etch pits in GaP, namely the formation of D and S pits. Grooves
have been produced on certain crystallographic orientations which are associated with certain types of stacking faults. It
is now possible to use this etch for a direct count of the dislocation density in (001) GaP and to indicate the extent of
stacking faults. 相似文献
73.
借助X射线衍射和扫描电子显微镜研究了Au和GaP接触体系界面特性的温度依赖性。测量表明,既使在低于400℃温度下界面反应也会生成少量的Au-GaP金属间化合物,它的主要成份是(GaAu)H,Ga2Au,在较高温度550℃合金条件下界面反应生成少量的GaP化合物表面发生分解,界面反应增增并伴随着快速的原子间互扩散,大量Ga原子向外迁移进入Au膜复盖层。同时,Au原子也内扩散进入GaP表面,Au-GA 相似文献
74.
75.
Second-order nonlinear optical materials for efficient generation and amplification of temporally-coherent and narrow-linewidth terahertz waves 总被引:1,自引:0,他引:1
We have considered forward and backward optical parametric oscillation and amplification, and difference-frequency generation for efficiently generating and amplifying terahertz waves in several second-order nonlinear optical materials. We have used a single crystal of CdSe as an example. We have also investigated GaSe, periodically-poled LiNbO3 and LiTaO3, and diffusion-bonded-stacked GaAs and GaP plates. The advantage of using birefringence in CdSe and GaSe is tunability of the output terahertz frequency. Furthermore, both CdSe and GaSe can be used to achieve the backward parametric oscillation without any cavity. On the other hand, in periodically-poled LiNbO3 and LiTaO3, one can take advantage of large diagonal elements of second-order nonlinear susceptibility tensor. In the diffusion-bonded-stacked GaAs and GaP plates, quasi-phase matching can be achieved by alternatively rotating the plates. We have shown that it is feasible to achieve forward optical parametric oscillation in the THz domain using these plates. The advantage of using coherent parametric processes is possibility of efficiently generating and amplifying temporally-coherent and narrow-linewidth terahertz waves. Compared with a noncollinear configuration, by using the parallel wave propagation configurations, the conversion efficiency can be higher because of longer effective interaction length among all the waves. 相似文献
76.
Andrew Y. Kim Michael E. Groenert Eugene A. Fitzgerald 《Journal of Electronic Materials》2000,29(8):L9-L12
Epitaxial transparent-substrate light-emitting diodes (ETS-LEDs) have been fabricated on optimized graded buffers of InxGa1−xP on GaP (∇x[InxGa1−x]P/GaP) that feature controlled threading dislocation densities of 3×106 cm−2. The ETSLEDs show increasing efficiency from 575 nm to 655 nm, in marked contrast to previous reports where performance drops
above 600 nm, and feature the lowest spectral widths ever reported in ∇x[InxGa1−x]P/GaP. The improvement over earlier reports is attributed to large mean dislocation spacings in optimized ∇x[InxGa1−x]P/GaP, which are an order of magnitude greater than the mean carrier diffusion length. A slight performance decline remains
at 655 nm, but the overall performance of this first generation of ETS-LEDs is promising. 相似文献
77.
K. A. Bell M. Ebert S. D. Yoo K. Flock D. E. Aspnes 《Journal of Electronic Materials》2000,29(1):106-111
We describe a modified commercial OMVPE reactor that incorporates quadrupole mass spectrometry (QMS) with a broadband parallel-processing optical spectrometer that simultaneously performs spectroscopic ellipsometry (SE) and reflectance-difference spectroscopy (RDS) measurements. We demonstrate its use by determining the surface temperature of Si to a precision of ±1°C and investigating the initial stages of GaP heteroepitaxy on Si(100). Analysis of the real-time SE data indicates that under our conditions GaP and Si interpenetrate as optically identifiable materials on a thickness scale of 100Å. 相似文献
78.
基于Mie散射理论,对磷化镓微球粒子从紫外光区到红外光区的光散射特性进行了数值计算与理论分析,得到了散射强度与散射角、粒子尺寸参数、偏振度与散射角以及光学截面与粒子尺寸参数的关系。结果表明,入射波长越长,粒子半径越小,散射越弱;并且在红外波段光散射很弱,在散射角90°方向上能观测到线偏振光,这为磷化镓材料的制备与应用提供了理论参考。 相似文献
79.
Sergei Pyshkin John Ballato Michael Bass Giorgio Turri 《Journal of Electronic Materials》2009,38(5):640-646
The results of luminescence studies conducted on the same samples of GaP over a 40-year period are discussed. The results
strongly imply that periodic ordering of impurities improved the overall optical and mechanical properties of the material
over time. Forty years after preparation, “hot” luminescence spectra in gallium phosphide (GaP) are similar to those for nanocrystals.
The aged pure and N-doped crystals exhibit stimulated emission at 300 K. The aged GaP:N:Sm at room temperature generates bright
green or yellow and red tunable luminescence. These results correlate with Raman light scattering and microhardness data obtained
from the same crystals. 相似文献
80.
表面粗化提高红光LED的光提取效率 总被引:2,自引:0,他引:2
介绍了通过出光表面粗糙化来减少全反射的方法,实验中使用化学湿法腐蚀的技术获得预计的粗糙形貌,结果给出不同参数下的光强和光辐射功率比较,器件的外量子效率得到了约29%的提高。从理论和测试结果两方面阐述了表面粗糙化对提高红光LED外量子效率的机理。 相似文献