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排序方式: 共有1068条查询结果,搜索用时 437 毫秒
71.
J. S. Kim D. G. Seiler R. A. Lancaster M. B. Reine 《Journal of Electronic Materials》1996,25(8):1215-1220
Variable-magnetic-field Hall measurements (0 to 1.5 T) are performed on very-narrow-gap bulk-grown Hg1−xCdxTe single crystals (0.165 ≤ x ≤ 0.2) at various temperatures (10 to 300K). The electron densities and mobilities are obtained
within the one-carrier (electrons) approximation of the reduced-con-ductivity-tensor scheme. The present data together with
the selected data set reported by other workers exhibit a pronounced peak when the electron mobility is plotted against the
alloy composition x-value which has been predicted to be due to the effective-mass minimum at the bandgap-crossing (Eg ≈ 0). The observed position (x ≈ 0.165), height (≈4 x 102 m2Vs), and width (≈0.01 in x) of the mobility-peak can be explained by a simple simulation involving only ionized-impurity scattering.
A lower bound of the effective mass is introduced as a fitting parameter to be consistent with the finiteness of the observed
electron mobility and is found to be of the order of 10−4 of the mass of a free electron. 相似文献
72.
P. Mitra Y. L. Tyan F. C. Case R. Starr M. B. Reine 《Journal of Electronic Materials》1996,25(8):1328-1335
Controlled and effective p-type doping is a key ingredient forin situ growth of high performance HgCdTe photodiode detectors. In this paper, we present a detailed study of p-type doping with
two arsenic precursors in metalorganic chemical vapor deposition (MOCVD) of HgCdTe. Doping results from a new precursortris-dimethylaminoarsenic (DMAAs), are reported and compared to those obtained from tertiarybutylarsine (TBAs). Excellent doping
control has been achieved using both precursors in the concentration range of 3 × 1015-5 × 1017 cm−3 which is sufficient for a wide variety of devices. Arsenic incorporation efficiency for the same growth temperature and partial
pressure is found to be higher with DMAAs than with TBAs. For doping levels up to 1 × 1017 cm−3, the alloy composition is not significantly affected by DMAAs. However, at higher doping levels, an increase in the x-value
is observed, possibly as a result of surface adduct formation of DMAAs dissociative products with dimethylcadmium. The activation
of the arsenic as acceptors is found to be in the 152–50% range for films grown with DMAAs following a stoichiometric anneal.
However, a site transfer anneal increases the acceptor activation to near 100%. Detailed temperature dependent Hall measurements
and modeling calculations show that two shallow acceptor levels are involved with ionization energies of 11.9 and 3.2 meV.
Overall, the data indicate that DMAAs results in more classically behaved acceptor doping. This is most likely because DMAAs
has a more favorable surface dissociation chemistry than TBAs. Long wavelength infrared photodiode arrays were fabricated
on P-on-n heterojunctions, grownin situ with iodine doping from ethyl iodide and arsenic from DMAAs on near lattice matched CdZnTe (100) substrates. At 77K, for
photodiodes with 10.1 and 11.1 (im cutoff wavelengths, the average (for 100 elements 60 × 60 μm2 in size) zero-bias resistance-area product, R0A are 434 and 130 ohm-cm2, respectively. Quantum efficiencies are ≥50% at 77K. These are the highest R0A data reported for MOCVDin situ grown photodiodes and are comparable to state-of-the-art LPE grown photodiodes processed and tested under identical conditions. 相似文献
73.
Molecular beam epitaxial HgCdTe material characteristics and device performance: Reproducibility status 总被引:1,自引:0,他引:1
J. Bajaj J. M. Arias M. Zandian J. G. Pasko L. J. Kozlowski R. E. De Wames W. E. Tennant 《Journal of Electronic Materials》1995,24(9):1067-1076
Extensive material, device, and focal plane array (FPA) reproducibility data are presented to demonstrate significant advances
made in the molecular beam epitaxial (MBE) HgCdTe technology. Excellent control of the composition, growth rate, layer thickness,
doping concentration, dislocation density, and transport characteristics has been demonstrated. A change in the bandgap is
readily achieved by adjusting the beam fluxes, demonstrating the flexibility of MBE in responding to the needs of infrared
detection applications in various spectral bands. High performance of photodiodes fabricated on MBE HgCdTe layers reflects
on the overall quality of the grown material. The photodiodes were planar p-on-n junctions fabricated by As ion-implantation
into indium doped, n-type, in situ grown double layer heterostructures. At 77K, diodes fabricated on MBE Hg1−xCdxTe with x ≈ 0.30 (λco
≈ 5.6 μm), x ≈ 0.26 (λco
≈ 7 μm), x ≈ 0.23 (λco ≈ 10 μm) show R0A products in excess of 1 x 106 ohm-cm2, 7 x 105 ohm-cm2, and 3 x 102 ohm-cm2, respectively. These devices also show high quantum efficiency. As a means to assess the uniformity of the MBE HgCdTe material,
two-dimensional 64 x 64 and 128 x 128 mosaic detector arrays were hybridized to Si multiplexers. These focal plane arrays
show an operability as high as 97% at 77K for the x ≈ 0.23 spectral band and 93% at 77K for the x ≈ 0.26 spectral band. The
operability is limited partly by the density of void-type defects that are present in the MBE grown layers and are easily
identified under an optical microscope. 相似文献
74.
报道了一种新型高灵敏浸没型HgCdTe红外探测器的研制,获得了D^*=1.46×10^11cmHz^1/2W^-1,R=608V/W,λc(20%)-20μ,灵敏元面积A=0.12×0.12mm^2,和有效通光孔径ψ=6mm的浸没型器件。 相似文献
75.
用傅里叶变换红外扫描光致发光方法研究了Hg1-xCdxTe体单晶样品,该方法可直接得到HgCdTe晶片组分的二维平面分布,并可得到辐射复合在复合机制中所占比重的平面分布,以及晶体中非平衡载流子寿命的分布 相似文献
76.
P-on-n mercury cadmium telluride (MCT) heterostructures grown by MOCVD with As and In as n- and p-type dopants, respectively,
are examined by measuring the Seebeck and Hall coefficients between 20 and 320K. The results are analyzed regarding doping
and composition of the layers by least squares fitting the experimental profiles with the calculated temperature dependencies.
The electron and hole densities of the layers are calculated taking into account Fermi-Dirac statistics, a nonparabolic conduction
band, a parabolic valence band, a discrete acceptor level, and fully ionized donors. For the Seebeck coefficient, the relation
we previously showed to be valid for p-type MCT1 is used. This relation relies on the thermoelectric effect in a temperature gradient resulting from the diffusion of nondegenerate
carriers scattered by LO-phonons. It also fits the observed thermoelectric properties of n-type MCT in a wide temperature
range. The doping and structural parameters determined from the thermoelectric measurements agreed very well with As and In
profiles obtained from secondary ion mass spectroscopy measurements and the data obtained from analyses of infrared transmission
measurements. 相似文献
77.
光导器件及其背景限探测度 总被引:1,自引:0,他引:1
本文就MCT光导型探测器作一总结性的讨论,对光导器件的扫出问题作了更详尽的阐述,并定义了扫出因子。关于背景限探测度提出了新的见解,认为背景限探测度不是不可逾越。 相似文献
78.
L. O. Bubulac J. Bajaj W. E. Tennant M. Zandian J. Pasko W. V. Mc Levige 《Journal of Electronic Materials》1996,25(8):1312-1317
This work presents characterization of implanted and annealed double layer planar heterostructure HgCdTe for p-on-n photovoltaic
devices. Our observation is that compositional redistribution in the structure during implantation/ annealing process differs
from that expected from classical composition gradient driven interdiffusion and impacts the placement of the electrical junction
with respect to the metallurgical heterointerface, which in turn affects quantum efficiency and RoA. The observed anomalous interdiffusion results in much wider cap layers with reduced composition difference between base
and cap layer composition. The compositional redistribution can, however, be controlled by varying the material structure
parameters and the implant/anneal conditions. Examples are presented for dose and implanted species variation. A model is
proposed based on the fast diffusion in the irradiation induced damage region of the ion implantation. In addition, we demonstrate
spatial uniformity obtained on molecular beam epitaxy (MBE) material of the compositional and implanted species profile. This
reflects spatial uniformity of the ion implantation/annealing Processes and of the MBE material characteristics. 相似文献
79.
The Hg0.8Cd0.2Te type-conversion, Hg self-diffusion and interdiffusion processes are analyzed in the context of a first order reaction kinetics
approach. Sets of nonlinear, stiffly coupled continuity equations are presented which describe the underlying physics, and
their solutions model the observed macroscopic behavior. It is demonstrated that the Frenkel pair mechanism interactions dominated
by the cation sublattice, in conjunction with basic diffusive and drift properties of the ionized point defects, comprise
the basic processes which effect all macroscopic phenomena discussed. Existing experimental results are reviewed and apparent
discrepancies discussed. Use is made of the Stanford University mercury cadmium telluride process simulator to provide quantitative
and insightful examples of important results. 相似文献
80.
Modeling ion implantation of HgCdTe 总被引:2,自引:0,他引:2
H. G. Robinson D. H. Mao B. L. Williams S. Holander-Gleixner J. E. Yu C. R. Helms 《Journal of Electronic Materials》1996,25(8):1336-1340
Ion implantation of boron is used to create n on p photodiodes in vacancy-doped mercury cadmium telluride (MC.T). The junction
is formed by Hg interstitials from the implant damage region diffusing into the MC.T and annihilating Hg vacancies. The resultant
doping profile is n+/n-/p, where the n+ region is near the surface and roughly coincides with the implant damage, the n- region is where Hg vacancies have been annihilated revealing a residual grown-in donor, and the p region remains doped by
Hg vacancy double acceptors. We have recently developed a new process modeling tool for simulating junction formation in MC.T
by ion implantation. The interstitial source in the damage region is represented by stored interstitials whose distribution
depends on the implant dose. These interstitials are released into the bulk at a constant, user defined rate. Once released,
they diffuse away from the damage region and annihilate any Hg vacancies they encounter. In this paper, we present results
of simulations using this tool and show how it can be used to quantitatively analyze the effects of variations in processing
conditions, including implant dose, annealing temperature, and doping background. 相似文献