Growth of AlGaN epitaxial film with high Al content by metalorganic chemical vapour deposition

A high-Al-content AlGaN epilayer is grown on a low-temperature-deposited AlN buffer on (0001) sapphire by low pressure metalorganic chemical vapour deposition. The dependence of surface roughness, tilted mosaicity, and twisted mosaicity on the conditions of the AlGaN epilayer deposition is evaluated. An AlGaN epilayer with favourable surface morphology and crystal quality is deposited on a 20 nm low-temperature-deposited AlN buffer at a low V/III flow ratio of 783 and at a low reactor pressure of 100 Torr, and the adduct reaction between trimethylaluminium and NH3 is considered.

FIELD-EFFECT ON THERMAL EMISSION FROM THE 0.40 EV ELECTRON LEVEL IN INGAP

Results are reported of electric-field dependence on thermal emission of electrons from the 0.40 eV level at various temperatures in InGaP by means of deep-level transient spectroscopy. The data are analyzed according to the Poole-Frankel emission from the potentials which are assumed to be Coulombic, square well, and Gaussian, respectively. The emission mte from this level is strongly field dependent. It is found that the Gaussian potential model is more reasonable to describe the phosphorus-vacancy-induced potential in InGaP than the Coulombic and square-well ones.

波矢方向对二维光子晶体能带及应用的影响

利用平面波法分析了由介电常数为13和1的两种介质分别构成圆形柱和背景组成的三角晶格、蜂巢状晶格和正方晶格，波矢偏离周期性平面对它们能带分布及应用的影响。波矢偏离周期性平面分量增加，对色散曲线的影响表现在

一个易于系统集成的变步长反馈数字DC-DC变换模块

提出了一种采用单比较器变步长反馈控制和占空比抖动方法的数字DC-DC变换模块。它用6位二进制分辨率占空比的PWM信号实现了7位的电压分辨率。变步长反馈控制的使用使得它具有比恒定步长方案更好的动态性能，而且没有过多增加控制器的复杂度。在1MHz的开关频率下，控制器自身功耗小于0.5mW（不含功率开关及驱动部分）。由于电路的模拟部分极少，因此易与数字系统进行单芯片集成。

横向外延GaN结晶质量的同步辐射研究

采用同步辐射X光衍射技术研究了α-Al_2O_3(0001)衬底上横向外延GaN的结构特征。发现横向生长区的GaN（0001）晶面与窗口区的GaN(0001)晶面在垂直掩模方向上存在取向差。ω/2θ联动扫描发现横向生长区的GaN的衍射峰半高宽约为窗口区GaN的一半，这表明横向外延生长技术在降低GaN穿透位错密度的同时，还能大幅度提高GaN的晶粒尺寸。

非晶硅太阳电池的正向注入电流检测磁共振研究

于2010-11-23批量导入

Real-time far distance micro-vibration measurement using an external cavity semiconductor laser interferometer with a feedback control system

An external cavity semiconductor laser interferometer used to measure far distance micro-vibration in real time is proposed. In the interferometer, a single longitudinal mode and excellent coherent characteristic grating external cavity semiconductor laser is constructed and acted as a light source and a phase compensator. Its coherent length exceeds 200 meters. The angle between normal and incidence beam of the far object is allowed to change in definite range during the measurement with this interferometer, and this makes the far distance interference measurement easier and more convenient. Also, it is not required to keep the amplitudes of the first and second harmonic components equal, and then the dynamic range is increased. A feedback control system is used to compensate the phase disturbance between the two interference beams introduced by environmental vibration.

Testing a single-aliquot protocol for recuperated OSL dating

IEECAS SKLLQG

岭南东江流域mis2阶段红色沙质沉积物粒度分布特征分析

IEECAS SKLLQG