Improved device reliability in organic light emitting devices by controlling the etching of indium zinc oxide anode

A controllable etching process for indium zinc oxide （IZO） films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices （OLEDs）, a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide （ITO） anode etched by a conventional strong etchant of aqua regia.     

金属Zr中自间隙子扩散的分子动力学模拟

本文采用分子动力学方法,对HCP结构的金属锆中的自间隙子扩散进行研究。通过检查不同时刻维格纳原胞(Wigner-Seitz cell)中的原子个数的方法得到不同时刻缺陷的位置,应用Rahman-Parrinello应力控制方法计算出了外应力为零时α-Zr的4种不同扩散机制在不同温度下的扩散系数,通过扩散系数随温度变化的关系得到各种扩散机制的势垒。     

Effects of Flow Rate Variation on SiCln （n 〈 3） Densities in SICl4 Plasmas

Radicals produced by the plasma enhanced chemistry vapour deposition technique in SiCl4 plasma are identified by mass spectrometry using our newly proposed straight-line fit method. Since flow rate is one of the most important parameters in depositing thin films, we present the effects of SiCl4 flow rate variation on SiCln （n 〈 3） densities. The experimental results demonstrate that Si and SiCln （n = 1, 2） densities decrease with increasing SiCl4 flow rate. After reaching the minimum values at a flow rate of 17 and 13sccm, respectively, Si and SiCln （n = 1, 2） densities slightly increase with further increase of flow rate to 20.5sccm. These results could be interpreted to which the depletion fraction of SiCl4 decreases and the residence time of SiCl4 molecule becomes shorter, with the increasing SICl4 flow rate. In order to obtain high-quality poly-Si films with high growth rate, it is better to use smaller flow rate of SICl4 source gas for depositing films.     

Spatial distribution of SiCln （n=O-2） in SICl4 plasma measured by mass spectroscopy

For a better understanding of the deposition mechanism of thin films in SiCl4 source gas, we have measured the spatial distributions of SiCln （n=0-2） radicals in SICl4 radio frequency glow discharge plasma utilizing a mass spectrometer equipped with a movable gas sampling apparatus. The experimental results demonstrate that the relative densities of SiCln （n=0-2） radicals have peak values at the position of 10 mm above the powered electrode along the axial direction; the relative densities of the Si and SiCIn （n=1, 2） radicals have peak values at the positions of 27mm and 7 mm away from the axis along the radial direction, respectively. Generally speaking, in the whole SICl4 plasma bulk region, the relative density of Si is one order of magnitude higher than that of SICl, and the relative density of SiCl is several times higher than that of SICl2. This reveals that Si and SiCl may be the primary growth precursors in forming thin films.     

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设计了一个取样位置能在射频辉光放电等离子体电极间自由移动的取样装置,用质谱计测量了SiCl4等离子体的离子信号。提出了一种线性拟合的方法用于计算SiCl4等离子体的消耗率,利用测量的离子信号,计算出了SiCl4等离子体中SiCln(n=0~2)中性基团的空间分布。实验结果表明,可移动质谱取样装置的设计是合理的;用线性拟合方法得到的等离子体消耗率和中性基团的相对密度,比以前的方法得到的更精确。     

Investigation on dependence of BiFeO3 dielectric property on oxygen content

The influence of oxygen content on the dielectric property of BiFeO3 ceramics is studied by experiment and firstprinciples calculation.The experimental result demonstrates that the dielectric constant of BiFeO3 is strongly dependent on introduced oxygen and oxygen vacancies.By comparison with BiFeO3,the introduced oxygen and oxygen vacancies can lead to a reduction in dielectric constant of BiFeO δ at a lower frequency.The first-principles calculation also shows a similar result when photon energy is in a range of 2.0-4.1 eV.A likely explanation is that this oxygen content dependence may be ascribed to the distortion of Fe-O octahedron structure due to oxygen vacancies or excess oxygen ions in the crystal structure of BiFeO3.