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991.
R. S. Goldman R. M. Feenstra B. G. Briner M. L. O’Steen R. J. Hauenstein 《Journal of Electronic Materials》1997,26(11):1342-1348
We have investigated the nanometer-scale structure and electronic properties of nitride/arsenide superlattices produced by
nitridation of a molecular beam epitaxially grown GaAs surface. Using cross-sectional scanning tunneling microscopy and spectroscopy,
we find that the nitrided layers are not continuous films, but consist of groups of atomic-scale defects and larger clusters.
We identify the defects and clusters as NAs and GaN with dilute As concentration, respectively. Thus, the nitrided regions consist of alloys from both sides of the miscibility
gap predicted for the GaAsN system. In addition, spectroscopy on the clusters reveals an upward shift of the band edges and
band gap narrowing, with significant change in the conduction band structure. We estimate the contribution of strain to band
gap narrowing in terms of an elasticity calculation for a coherently strained spherical GaN cluster embedded in GaAs. 相似文献
992.
O. Briot B. Gil M. Tchounkeu R. L. Aulombard F. Demangeot J. Frandon M. Renucci 《Journal of Electronic Materials》1997,26(3):294-300
We address combined utilization of temperature dependent reflectance, photo-luminescence, and Raman spectroscopy measurements
to optimize the struc-tural and electronic properties of GaN epilayers deposited on sapphire. Last, we study residual strain
fields in such epilayers. 相似文献
993.
I. K. Shmagin J. F. Muth R. M. Kolbas S. Krishnankutty S. Keller A. C. Abare L. A. Coldren U. K. Mishra S. P. Den Baars 《Journal of Electronic Materials》1997,26(3):325-329
Photoluminescence (PL) characteristics of GaN/lnGaN/GaN single quantum wells (QWs) and an InGaN/GaN single heterojunction were studied using continuous wave (CW) and pulsed photoluminescence in both edge and surface emitting configurations. Samples were grown on c-plane sapphire substrates by atmospheric pressure metalorganic chemical vapor deposition (MOCVD). Room temperature and 77K PL measurements were performed using a CW Ar-ion laser (305 nm) and a frequency tripled (280 nm), pulsed, mode-locked Ti: sapphire laser. CW PL emission spectra from the quantum wells (24, 30, 80Å) were all blue shifted with respect to the reference sample. The difference (i. e., the blue shift) between the measured value of peak emission energy from the QW and the band-edge emission from the reference sample was attributed to quantum size effects, and to strain arising due to a significant lattice mismatch between InGaN and GaN. In addition, stimulated emission was observed from an InGaN/GaN single heterojunction in the edge and surface emitting configu-ration at 77K. The narrowing of emission spectra, the nonlinear dependence of output emission intensity on input power density, and the observation of a strongly polarized output are presented. 相似文献
994.
995.
薛舫时 《固体电子学研究与进展》2012,32(6):517-523,560
从自洽求解薛定谔方程和泊松方程出发,研究了GaN异质结构上偏压变化时异质结电场的变化。发现异质结量子阱能把外电场屏蔽在异质界面以外。利用这种异质结量子阱的屏蔽效应,可以使外电场都降落在异质结表面来控制表面势。为了把表面电势剪裁成半导体阴极所需的陡直下降的电势结构,进一步深入研究了双势垒异质结的电场结构,发现外面的异质结能屏蔽里面异质结的势垒。利用这种双势垒异质结的屏蔽效应设计出可由偏压直接控制电子亲合势的异质结构,从而为半导体阴极开辟出一条新的研究途径。 相似文献
996.
997.
Chemical mechanical polishing (CMP) has been used to produce smooth and scratch-free surfaces for GaN. In the aqueous solution of KOH, GaN is subjected to etching. At the same time, all surface irregularities, including etch pyramids, roughness after mechanical polishing and so on will be removed by a polishing pad. The experiments had been performed under the condition of different abrasive particle sizes of the polishing pad. Also the polishing results for different polishing times are analyzed, and chemical mechanical polishing resulted in an average root mean square (RMS) surface roughness of 0.565 nm, as measured by atomic force microscopy. 相似文献
998.
研究了Al GaN/GaN HEMT制备中相关工艺对器件肖特基特性的影响,并对工艺进行了优化。首先研究了表面处理对器件肖特基势垒特性的影响,对不同的表面处理方法进行了比较,发现采用氧等离子体处理,并用V(HF)∶V(H2O)=1∶5溶液清洗刻蚀后的表面,可以有效减小表面态密度,未经处理的样品肖特基接触理想因子为2.6,处理后理想因子减小到1.8。对Si N钝化膜的折射率与肖特基特性的关系进行了研究,发现Si N钝化膜的折射率为2.3~2.4时,钝化对肖特基特性的影响较小,但反向泄漏电流较大。 相似文献
999.
通过阐述外延薄膜进行原位监测的反射高能电子衍射(RHEED)以及RHEED图像的条纹或点阵与GaN基薄膜表面形貌的关系,提出了基于RHEED图像分析外延GaN基薄膜晶体结构演变情况,从衬底α-Al2O3的氢氮等离子体清洗、氮化、生长缓冲层以及生长外延层进行具体的分析、比较和演算.结果表明衬底在清洗前后表面晶格常数基本保持一致,对于氮化层、缓冲层以及外延层情况,表面原子层处于应变状态. 相似文献
1000.
为系统解决高电压复杂电磁场环境塔基设备供电问题,提出一种基于GaN(氮化镓,第三代半导体材料)器件的多米诺中继型无线供电系统及配置方法。首先基于电路互感耦合模型和有限元仿真对多米诺无线供电系统的频率特性和功效特性进行了分析,发现通过调节负载阻抗匹配和适当提高驱动频率,能够有效改善系统的传输功效特性和抗频率失调特性,并结合电场分布云图对系统的电磁兼容性进行验证。在此基础上搭建基于GaN器件的多米诺无线供电系统实验样机,测试结果表明该系统能够实现高电压等级远距离、高效率的无线供电,且具有较好的抗频率失调特性,为无线电能传输技术在高电压设备供电领域的应用提供了参考依据。 相似文献