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21.
Self-assembled quantum dots capping with a GaAs/Gasb combined strain-reduced layer (CSRL) are grown by MBE. Their structural and optical properties are investigated by AFM and photoluminescence (PL). PL measurements have shown that stronger emission about 1.3μm can be obtained by Sb irradiation and capping QDs with 3 ML GaAs/2 ML GaSh CSRL at room temperature. The full width at half maximum (FWHM) of the PL spectrum is about 20.2 meV (19.9 meV) at room temperature (2OK), indicating that the QDs have high uniform, The result of FWHM is much better than the recently reported result, which is due to the fact that lower QD growth rate and growth interruption after the QDs deposition are adopted in our experiments. 相似文献
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对使用金属有机物汽相沉积法生长的AlGaN/AlN/GaN结构进行的变温霍尔测量,测量结果指出在AlN/GaN界面处有二维电子气存在且迁移率和浓度在2K时分别达到了1.4×104cm2·V-1·s-1和9.3×1012cm-2,且在200K到2K范围内二维电子气的浓度基本不变,变磁场霍尔测量发现只有一种载流子(电子)参与导电.在2K温度下,观察到量子霍尔效应,Shubnikov-de Haas (SdH) 振荡在磁场约为3T时出现,证明了此结构呈现了典型的二维电子气行为.通过实验数据对二维电子气散射过程的半定量分析,推出量子散射时间为0.23ps,比以往报道的AlGaN/GaN结构中的散射时间长,说明引入AlN层可以有效减小合金散射,进一步的推断分析发现低温下以小角度散射占主导地位. 相似文献
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Coulomb blockade oscillations of Si single-electron transistors, which are fabricated completely by the conventional photolithography technique, have been investigated. Most of the single-electron transistors clearly show Coulomb blockade oscillations and these oscillations can be periodic by applying negative voltages to the in-plane gates. A shift of the peak positions is observed at high temperatures. It is also found that the fluctuation of the peak spacing cannot be neglected. 相似文献
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Single electron transistors with wire channels are fabricated by a nanoelectrode-pair technique. Their characteristics strongly depend on the channel widths and the voltages on the in-plane gates. A few dips in the Coulomb blockade oscillations were observed at the less positive gate voltages for a device with a 70nm-wide wire due to Coulomb blockade between the coupled dots. By applying negative voltages to the in-plane gates, the oscillations became periodic, which indicated the formation of a single dot in the conducting channel. These gates facilitate fabricating single-electron transistors with single dot structures, which have potential applications on its integration. 相似文献
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ZnO nanostructures with different morphologies were fabricated by changing the partial oxygen pressure. The structures, morphologies and optical properties of ZnO nanostructures were investigated by x-ray diffraction, field emission scanning electron microscopy and photoluminescence (PL) spectra at room temperature. All the samples show preferred orientation along the c-axis. The oxygen partial pressure and the annealing atmosphere have important effect on the PL property of ZnO nanostructures. The high oxygen partial pressure during growth of samples and high-temperature annealing of the ZnO samples in oxygen can increase oxygen vacancies and can especially increase antisite oxygen (OZn) defects, which degraded the near band-edge emission. However, the annealing in 1-12 can significantly modify the NBE emission. 相似文献
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Properties of InGaP/GaAs Grown by Solid-Source Molecular Beam Epitaxy with a GaP Decomposition Source 下载免费PDF全文
Lattice-matched InGaP on GaAs (001) was successfully grown by solid-source molecular beam epitaxy witha GaP decomposition source. A 0.5-μm-thick InGaP epilayer shows photoluminescence peak energy as large as 1.991eV at 15K, the full width at half maximum as small as 9.4meV and x-ray diffraction rocking curve linewidth as narrow as 25 arcsec. The electron mobilities of undoped and Si-doped InGaP layers obtained by Hall measurements are comparable to similar InGaP/GaAs heterojunction grown by solid-source molecular beamepitaxy with other sources or other growth techniques. The results reveal that the InGaP/GaAs heterojunction grown bY the present growth way have great potential applications for semiconductor devices. 相似文献
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