Hot carrier magnetophonon spectroscopy of semiconductors in high magnetic fields up to 40 T

Hot carrier magnetophonon resonances of n-type Si, short channel InP and p-type InSb were investigated in pulsed high magnetic fields up to 40 T. Using a recently developed high resolution technique in pulsed high fields, many new features of the hot carrier-phonon interactions in high magnetic fields were found.     

预压缩单晶镍基合金的组织结构及在拉伸蠕变期间的粗化特征

对[001]取向单晶镍基合金进行压应力处理，获P-型筏状结构后，对其进行拉伸蠕变性能测试及SEM形貌观察，研究了P-型筏状结构的粗化特征及影响因素。结果表明：由于应力场的差别，样品不同位置筏状γ＇相粗化程度及特征不同，近断口处筏状γ＇相扭曲且粗化程度加剧，随离断口距离增加，γ＇相粗化程度减弱。有限元分析认为：外加载荷改变了水平和垂直γ基体通道中的错配应力分布，并使立方γ＇相不同界面晶格发生挤压或扩张应变，这可以促进元素的互扩散和γ＇相的定向生长，是形成P-型筏状组织的主要原因。在高温及拉应力作用下，P-型γ＇相端部沿垂直于应力轴方向优先生长和相互横向连接，并进一步形成折叠的层状组织。     

P型CuAlO2半导体陶瓷的烧结研究

性能良好的陶瓷靶材是溅射法制备薄膜的先决条件.本文以纳米级Al2O3粉体和微米级Cu2O粉体为原料通过烧结的方法制备了P型透明导电氧化物陶瓷CuAlO2.以X射线衍射和SEM分析的方法研究了烧结温度对反应进行的影响,并在合适的温度区间里得到了具有较好P型半导体性能的陶瓷,其迁移率达到27 cm2·V-1·s-1.以它作为靶材通过真空溅射得到了迁移率为2.1 cm2·V-1·s-1的P型透明半导体薄膜.     

Comments on “Robust optimal design and convergence properties analysis of iterative learning control approaches” and “On the P-type and Newton-type ILC schemes for dynamic systems with non-affine input factors”

The papers by Xu and Tan [Robust optimal design and convergence properties analysis of iterative learning control approaches, Automatica 38 (2002) 1867-1880], and Xu and Tan [On the P-type and Newton-type ILC schemes for dynamic systems with non-affine input factors, Automatica 38 (2002) 1237-1242], give a convergence analysis for several iterative learning control approaches. Unfortunately, these papers contains several mathematical errors that render the proofs of the claimed results invalid. As there are no obvious ways to correct these errors, the results presented in these papers are questionable.     

Fabrication and characterization of all-oxide heterojunction p-CuAlO2 + x/n-Zn1 − xAlxO transparent diode for potential application in “invisible electronics”

Transparent p-n heterojunction diodes have been fabricated by p-type copper aluminum oxide (p-CuAlO_2 + x) and n-type aluminum doped zinc oxide (n-Zn_1 − xAl_xO) thin films on glass substrates. The n-layers are deposited by sol-gel-dip-coating process from zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O) and aluminum nitrate (Al(NO₃)₃·9H₂O). Al concentration in the nominal solution is taken as 1.62 at %. P-layers are deposited onto the ZnO:Al-coated glass substrates by direct current sputtering process from a prefabricated CuAlO₂ sintered target. The sputtering is performed in oxygen-diluted argon atmosphere with an elevated substrate temperature. Post-deposition oxygen annealing induces excess oxygen within the p-CuAlO_2 + x films, which in turn enhances p-type conductivity of the layers. The device characterization shows rectifying current-voltage characteristics, confirming the proper formation of the p-n junction. The turn-on voltage is obtained around 0.8 V, with a forward-to-reverse current ratio around 30 at ± 4 V. The diode structure has a total thickness of 1.1 μm and the optical transmission spectra of the diode show almost 60% transmittance in the visible region, indicating its potential application in ‘invisible electronics’. Also the cost-effective procedures enable the large-scale production of these transparent diodes for diverse device applications.     

Characterization of MgxZn1 − xO thin films grown on sapphire substrates by metalorganic chemical vapor deposition

Wurtzite-structure Mg_xZn_1 − xO materials with five different compositions of x from 0 to 0.14 were grown on sapphire substrates by metalorganic chemical vapor deposition. It was found that increasing Mg content in the Mg_xZn_1 − xO not only increased the band gap energy of the film but was also beneficial to the epitaxial growth of p-type Mg_xZn_1 − xO without using any doping sources. In addition, the combined ultraviolet photoluminescence (PL) and Raman scattering spectra were measured with PL-Raman signals obtained together, showing a blue-shift of PL band and variation of resonant Raman multi-order longitudinal optical phonon modes with an increase of Mg content.     

P型TiOx半导体薄膜的特性研究与制备

TiO2陶瓷在射频溅射过程中表面成分发生改变，变化后的陶瓷表面具有良好的导电性，可作为靶材采用直流溅射法在玻璃基片上制备TiO2薄膜，发现当工作气体中不通O2时溅射得到的TiO2薄膜由于氧缺位呈N型导电，而当预先在玻璃衬底上沉积一层金属Ti时TiO2薄膜的导电类型发生了转变，由N型导电转向P型导电，该文对这一现象进行了研究，并讨论了钛层厚度和真空退火条件对薄膜P型导电性质的影响。     

高水头平面闸门P型水封变形特性及止水性能研究

建立高水头平面闸门P型水封的非线性有限元模型,对其止水过程进行模拟。模型中考虑水封橡胶材料的非线性和不可压缩性、高水头作用下水封大变形导致的几何非线性以及水封与压板、水封与止水座板的接触非线性边界条件。通过非线性有限元分析,得到P型水封的接触应力、接触宽度等情况,研究P型水封的变形特性及止水性能,并分析水封垫板宽度对P型水封变形特性及止水性能的影响,为实际工程中P型水封的设计提供有益的指导。     

退化高阶抛物型分布参数系统的迭代学习控制

研究一类高阶分布参数系统的迭代学习控制问题,该类系统由退化高阶抛物型偏微分方程构成.根据系统所满足的性质,基于P型学习算法构建得到迭代学习控制器.利用压缩映射原理,证明该算法能使得系统的输出跟踪误差于L~2空间内沿迭代轴方向收敛于零.最后,仿真算例验证了算法的有效性.     

Fabrication and post-anneal activation of p-type ZnMgO:Li film using dc reactive magnetron sputtering

Monodoping Li as acceptor, p-type ZnMgO thin films have been realized via dc reactive magnetron sputtering followed by a thermal anneal process. The conductivity of Li-doped films are transformed from highly resistant to p-type via anneal. This phenomenon may be associated with eliminating of Li_Zn–Li_i complexes and Li_i. The optimized p-type Zn_0.96Mg_0.04O:Li thin film possesses a resistivity of 72.3Ω cm and a carrier concentration of 1.49 × 10¹⁷cm^{− 3}, while the electrical properties of Zn_0.84Mg_0.16O:Li thin film degrade in comparison to Zn_0.96Mg_0.04O:Li thin film. Moreover, the absorption spectra confirm Mg can be a good candidate for band gap engineering in p-type ZnO film.