全文获取类型
收费全文 | 81篇 |
免费 | 93篇 |
国内免费 | 4篇 |
专业分类
化学 | 9篇 |
晶体学 | 35篇 |
物理学 | 134篇 |
出版年
2023年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 10篇 |
2012年 | 23篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 12篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1983年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有178条查询结果,搜索用时 31 毫秒
151.
利用直流辉光放电等离子体辅助的脉冲激光沉积技术在Si衬底上生长了碳氮薄膜.通过扫描电子显微镜、X射线衍射、X射线光电子能谱、俄歇电子能谱等多种手段,对薄膜的形貌、成分、晶体结构、价键状态等特性进行了分析和确定.结果表明,沉积薄膜为含有非晶SiN和晶态氮化碳颗粒结构,晶态成分呈多晶态,主要为α-C3N4相、β-C3N4相,晶粒大小为40—60nm.碳氮之间主要以C-N非极性共价键形式相结合.
关键词:
脉冲激光沉积
直流辉光放电
碳氮薄膜 相似文献
152.
轰击阴极的重粒子能量分布 总被引:2,自引:2,他引:0
采用蒙特卡罗模拟对氮辉光放电等离子体中轰击极阴的重粒子(N2^ ,N^ ,Nf及N2f)能量分布随放电参数的变化规律进行了研究。结果表明:阴极臂前诸粒子的能量分布取决于粒子被加速的能量和碰撞频率,能量较低的快原子Nf的密度比高能粒子N^ 的密度最近两个量级。在活性氮粒子(N^ ,Nf)产率最高的放电条件下,适当降低放电气压,提高阴极位降和气体温度,有利于两种活性氮粒子(N^ ,Nf)达到阴极。 相似文献
153.
154.
The microwave absorption dielectric spectrum can be used to study the decay process of free photoelectrons and shallow-trapped electrons in semiconductor crystals. The decay curve of free photoelectrons and shallow-trapped electrons of silver halide grains is measured using this technique. The influence of iodide and K_4Fe(CN)_6 shallow electron trap dopants on the photoelectron lifetime of silver halide grains is studied. For the unsensitized cubic AgCl crystals, when the free photoelectron lifetime (FLT) reaches a maximum, the photographic efficiency is optimal. From our analysis, we conclude that FLT is the longest for the cubic AgCl crystals doped with 0.5% iodide at 80% doping position and 1×10^{-6} mol K_4Fe(CN)_6/molAg, whereas, for the highly photosensitized cubic AgBrCl crystals doped with K_4Fe(CN)_6, the photographic efficiency is optimal when the FLT reaches its minimum. The free photoelectron lifetime reaches minimum and the sensitivity of AgBrCl emulsion reaches maximum when the doping position is 30%Ag at K_4Fe(CN)_6 content of 10^{-6}mol/molAg. 相似文献
155.
Electronic structure and defect states of transition films from amorphous to microcrystalline silicon studied by surface photovoltage spectroscopy
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this paper, surface photovoltage spectroscopy (SPS) is used to
determine the electronic structure of the hydrogenated transition Si
films. All samples are prepared by using helicon wave plasma-enhanced
chemical vapour deposition technique, the films exhibit a transition
from the amorphous phase to the microcrystalline phase with
increasing temperature. The film deposited at lower substrate
temperature has the amorphous-like electronic structure with two
types of dominant defect states corresponding to the occupied Si
dangling bond states (D0/D- and the empty Si dangling
states (D+). At higher substrate temperature, the
crystallinity of the deposited films increases, while their band gap
energy decreases. Meanwhile, two types of additional defect states is
incorporate into the films as compared with the amorphous
counterpart, which is attributed to the interface defect states
between the microcrystalline Si grains and the amorphous matrix. The
relative SPS intensity of these two kinds of defect states in samples
deposited above 300\du increases first and decreases afterwards,
which may be interpreted as a result of the competition between
hydrogen release and crystalline grain size increment with increasing
substrate temperature. 相似文献
156.
157.
The optical-optical double resonant multiphoton ionization (OODR-MPI) technique and the fluorescent excitation spectroscopy technique have been applied to the study of the F′0+u ion-pair state of iodine. This paper presents OODR-MPI spectrum and fluorescent excitation spectrum of I2 in the region of 54000-55300cm-1 by the three-photon resonant, two-photon ionization (1+2+2) and (1+(1+1)+2) processes. 相似文献
158.
基于文献[1],本工作在较高泵浦激光能通量范围,测量并研究了BCl3分子振动激发v_3吸收谱及时间演变,观察了v3激发弛豫的几种能量转移过程,以及对泵浦激光能量BCl3气压等参数的依赖关系。表明泵浦光脉冲产生一个振动态非热分布的系综,转动能量转移对引起这种非热分布有重要作用。用简化碰撞动力学模型讨论了BCl3振动激发吸收谱的演变过程,得到振动态再分布的简单关系;Pτv-v≌c/K′(Tv,T0,q)和等效振动温度、平均吸收光子数的分析表达式,与实验结果定性地符合。
关键词: 相似文献
159.
We investigate the decay process of photoelectrons from a luminescent material of ZnO:Zn using a microwave dielectric spectrometry. Electrons in the conduction band are found to decay exponentially and the lifetime is 781 ns, while the time interval of decay from the maximum to half of this value is 470ns. ZnO:Zn is a green luminescent material at its central wavelength of 510 nm. Compared to the decay of electrons in the conduction band, the decay process of the luminescence is faster, and the time interval of decay from the maximum to half of the maximum is about 100 ns. We believe that the mechanism of the ZnO:Zn visible luminescence is recombination luminescence, and find that our theoretical simulation is in agreement with the experimental results. 相似文献
160.
利用光学发射谱技术对螺旋波等离子体化学气相沉积纳米硅薄膜的等离子体内活性粒子的光发射特征进行了原位测量.研究了薄膜沉积过程中各实验参量对活性基团SiH*, Hβ以及Hα的发射谱强度的影响.实验结果表明,静态磁场的加入可显著提高反应气体 的解离效率 ;适当的氢稀释可以提高氢活性粒子的浓度,而过高的氢稀释比将使含硅活性基团浓度显著 减小;提高射频馈入功率整体上可以使各活性粒子的浓度增加,并有利于提高到达衬底表面 氢活性粒子的相对比例.结合螺旋波等离子体色散关系和等离子体特点对以上结果进行了分 析.该结果为螺旋波等离子体沉积纳米硅薄膜过程的理解及制备工艺参数的调整提供了基础 数据.
关键词:
光学发射谱
螺旋波等离子体化学气相沉积
纳米硅薄膜 相似文献