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101.
Jing Xiao Yue Wu Wei Zhang Xin Bai Ligang Yu Shiqi Li Gengmin Zhang 《Applied Surface Science》2008,254(17):5426-5430
Zinc oxide nanopencil arrays were synthesized on pyramidal Si(1 0 0) substrates via a simple thermal evaporation method. Their field emission properties have been investigated: the turn-on electric field (at the current density of 10 μA/cm2) was about 3.8 V/μm, and the threshold electric field (at the current density of 1 mA/cm2) was 5.8 V/μm. Compared with similar structures grown on flat Si substrates, which were made as references, the pyramidal Si-based ZnO nanopencil arrays appeared to be superior in field emission performance, thus the importance of the non-flat substrates has been accentuated. The pyramidal Si substrates could not only suppress the field screening effect but also improve the field enhancement effect during the field emission process. These findings indicated that using non-flat substrates is an efficient strategy to improve the field emission properties. 相似文献
102.
Bernd Tillack Bernd Heinemann Dieter Knoll Holger Rücker Yuji Yamamoto 《Applied Surface Science》2008,254(19):6013-6016
Incorporation of high doping concentrations and the creation and maintaining of steep doping profiles during processing are key enabler for high level RF performance of heterojunction bipolar transistors (HBTs). In this paper, we discuss results of base doping and dopant profile control for npn and pnp SiGe HBTs fabricated within 0.25 μm BiCMOS technologies. High level of electrically active B and P doping concentrations (up to 1020 cm−3) have been incorporated into SiGe. By adding C to SiGe steep doping profiles have been maintained due to the prevention of dopant diffusion during device processing. It is shown that broadening of P doping profiles caused by segregation could be reduced by lowering the deposition temperature for the SiGe cap. B and P atomic layer doping is shown to be suitable for the creation of steep and narrow doping profiles. This result is demonstrating the capability of the atomic layer processing approach for future devices with critical requirements of dopant dose and location control. 相似文献
103.
E. Simoen B. Vissouvanadin M. Bargallo Gonzalez P. Verheyen C. Claeys V. Machkaoutsan S. Thomas R. Wise 《Applied Surface Science》2008,254(19):6140-6143
This work investigates the impact of various processing parameters on the leakage current of in situ P-doped Si1−xCx embedded source/drain (S/D) junctions, i.e., the carbon content x (%) and the thermal budget used either before or after the selective epitaxial deposition. It is shown that while the area leakage current density, generated by defects in the depletion region is not affected by the epitaxial process or the strain in the substrate, the perimeter leakage current density (JP) increases with x. From the stronger reverse bias dependence of JP, it is derived that a higher electric field exists along the junction periphery. This is confirmed by capacitance-voltage (C-V) measurements, demonstrating a higher p-well B doping density for increasing x. It is believed that this originates from the strain dependence of the B diffusivity in the p-well region. No evidence of electrically active extended defect formation was found, so it is expected that the off-state current of embedded Si1−xCx S/D nMOSFETs will not be adversely affected by the selective epitaxial deposition. 相似文献
104.
Electronic Curves Crossing in Methyl Iodide by Spin--Orbit Ab Initio Calculation 总被引:1,自引:0,他引:1 下载免费PDF全文
An ab initio investigation of electronic curve crossing in a methyl iodide molecule is carried out using spin-orbit multiconfigurational quasidegenerate perturbation theory. The one-dimensional rigid potential curves and optimized effective curves of low-lying states, including spin-orbit coupling and relativistic effects, are calculated. The spin-orbit electronic curve crossing between ^3Qo+ and ^1Q1, and the shadow minimum in potential energy curve of ^3Qo+ at large internuclear distance are found in both sets of the curves according to the present calcu- lations. The crossing position is in the range of Re-1 = 0.2370 3:0.0001 nm. Comparisons with other reports are presented. 相似文献
105.
A Fock--Darwin system in noncommutative quantum mechanics is studied. By constructing Heisenberg algebra we obtain the levels on noncommutative space and noncommutative phase space, and give the corrections to the results in usual quantum mechanics. Moreover, to search the difference among the three spaces, the degeneracy is analysed by two ways, the valueof ω/ωc and certain algebra realization (SU(2)and SU(1,1)), and some interesting properties in the magnetic field limit are exhibited, such as totally different degeneracy and magic number distribution for the given frequency or mass of a system in strong magnetic field. 相似文献
106.
A Simple Route of Morphology Control and Structural and Optical Properties of ZnO Grown by Metal-Organic Chemical Vapour Deposition 下载免费PDF全文
Employing the metal-organic chemical vapour deposition (MOCVD) technique, we prepare ZnO samples with different morphologies from the film to nanorods through conveniently changing the bubbled diethylzinc flux (BDF) and the carrier gas flux of oxygen (OCGF). The scanning electron microscope images indicate that small BDF and OCGF induce two-dimensional growth while the large ones avail quasi-one-dimensional growth. X-ray diffraction (XRD) and Raman scattering analyses show that all of the morphology-dependent ZnO samples are of high crystal quality with a c-axis orientation. From the precise shifts of the 20 locations of ZnQ (002) face in the XRD patterns and the E2 (high) locations in the Raman spectra, we deduce that the compressive stress forms in the ZnO samples and is strengthened with the increasing BDF and OCGF. Photoluminescence spectroscopy results show all the samples have a sharp ultraviolet luminescent band without any defects-related emission. Upon the experiments a possible growth mechanism is proposed. 相似文献
107.
We show that in the Snyder space the area of the disc and of the sphere can be quantized. It is also shown that the area spectrum of the sphere can be related to the Bekenstein conjecture for the area spectrum of a black hole horizon. 相似文献
108.
P.D. Shidling N. Madhavan V.S. Ramamurthy S. Nath N.M. Badiger Santanu Pal A.K. Sinha A. Jhingan S. Muralithar P. Sugathan S. Kailas B.R. Behera R. Singh K.M. Varier M.C. Radhakrishna 《Physics letters. [Part B]》2008
Evaporation residue (ER) cross sections and gamma multiplicity distributions have been measured for 16O + 184W and 19F + 181Ta systems in the excitation energy range of 50–90 MeV, leading to the same compound nucleus 200Pb∗. Comparison of experimental results of both the systems shows that ER cross sections and moments of gamma multiplicity distribution of 16O + 184W system are significantly higher than those of 19F + 181Ta system at higher excitation energies. Present measurements directly shows the experimental signature of entrance channel effect even with the systems which are not very different with respect to their entrance channel mass asymmetry. It is further demonstrated that the reduction in the ER cross section and moments of spin distribution for 19F + 181Ta system is mainly due to the suppression of fusion of higher l values. 相似文献
109.
Pulak Ranjan Giri 《Physics letters. A》2008,372(31):5123-5125
We study non-commutative quantum mechanics and exploit the non-commutative parameter as a scale for a scale symmetric system. The Hamiltonian in non-commutative space allows an unusual bound state at the threshold of the energy, E=0. The so(2,1) algebra for the system is also studied in non-commutative space. 相似文献
110.
T.V. Fityo 《Physics letters. A》2008,372(37):5872-5877
We considered the thermodynamics in spaces with deformed commutation relations leading to the existence of minimal length. We developed a classical method of the partition function evaluation. We calculated the partition function and heat capacity for ideal gas and harmonic oscillators using this method. The obtained results are in good agreement with the exact quantum ones. We also showed that the minimal length introduction reduces degrees of freedom of an arbitrary system in the high temperature limit significantly. 相似文献