高温氨化合成GaN微晶

分别利用Ga2O3粉末和Ga2O3凝胶作为Ga源,采用NH3为N源,在950℃下,分别将两种反应物与流动的NH3反应20 min合成了GaN微晶。用X射线衍射(XRD)、扫描电子显微镜(SEM)、选择区电子衍射(SAED)对微晶进行结构、形貌的分析,特别是对两种不同途径合成GaN微晶的XRD进行了分析比较。结果表明,当Ga源温度为950℃时两种不同的合成途径均可得到六方纤锌矿结构的GaN单晶颗粒,在氮化温度为850℃和900℃时,利用Ga2O3粉末作为Ga源,仅有少量的Ga2O3转变为GaN;而采用Ga2O3凝胶作为Ga源,在相同的温度下,大部分凝胶经过高温氨化反应均可转化为GaN。     

钠化焙烧钒渣同时加碳氯化挥发镓的研究

考察了低温400℃和中温800℃条件下,添加活性碳及液体含碳物纸浆与钒渣、NaCl和Na_2CO_3混合焙烧时氯化挥发镓及钒转比为水溶性钒的情况。本实验得到的最高η_(Ga)为35.1％。焙烧料中不含Na_2CO_3和焙烧温度为400℃时,钒转比为水溶性钒的比率(ηv.t)较低。纸浆添加比L_(纸浆)为0.05mL/g、配料比W_(Na_2CO_3)/W_(Nacl)=2时,可望同时得到较高的η_(Ga)和(ηv.t)。     

从水淬渣中回收镓的试验研究

对鼓风炉（ISP法）或烟化炉水淬渣中回收镓的工艺进行了研究。结果表明，利用浓硫酸恒温熟化的独特浸出工艺，克服硅对液固分离的影响；以伯胺N9123作为萃取剂在硫酸介质中萃取镓；获得了含镓品位为2.82%的富集物。     

Optical and electrical characterization of fluorine doped cadmium oxide thin films prepared by the sol-gel method

Highly transparent and conducting fluorine (F) doped cadmium oxide (CdO) thin films were deposited on glass slides by the sol-gel method. The films were doped by the addition of ammonium fluoride to the precursor solution whose optimum concentration was determined. The films were fired in an open atmosphere at 350 °C and after that, exposed to annealing treatments in different atmospheres (N₂, N₂/H₂ mixture and Ar) at the same temperature. The films were characterized by ultraviolet-visible spectroscopy, X‐ray diffraction and scanning electron microscopy. The resistivity was determined by the four probes method and current-voltage measurements in accordance with the standard Van der Pauw configuration. The CdO:F thin films obtained, showed high polycrystalline quality and high transmission in the visible region (≥ 90%), shifting towards the blue region of the absorption edge as the fluorine concentration in the precursor solution was increased from 0 to 30 at.%. The lowest resistivity values were reached for the samples with F content higher or equal to 5% and annealed in either N₂ or a 96/4 N₂/H₂ gas mixture. Our resistivity value reached in the CdO:F layers was 4.5 × 10^{− 4} Ω cm (20 Ω/square).     

钠化焙烧钒渣时氯化挥发镓的热力学分析

本文讨论了６００～１２００Ｋ范围内使用ＮａＣｌ作为添加剂焙烧钒渣时氯化发镓的热力可靠性。结论是：氯氧比的大小与溶性钒酸钠生成有直接联系，ＮａＣｌ和Ｎａ２Ｏ。Ｖ２Ｏ５平衡时的氯氧比最大；在氯化钠作用下，镓主要生成ＧａＣｌ３挥发，计算得到的ＧａＣｌ３的生成压相当大。     

Improvement of photon collection in Cu(In,Ga)Se2 solar cells and modules by fluorescent frequency conversion

Fluorescent photon down conversion for the improvement of the blue response of ZnO/CdS/Cu(In,Ga)Se₂ heterojunction solar cells and modules is investigated. Fluorescent dyes of the series Lumogen® F are analyzed by optical transmission and reflection as well as by photoluminescence measurements. A spectral transfer matrix formalism is introduced that allows to predict the suitability of a luminescent dye as a down-converter for a given solar cell from its absorption/emission properties. We find that Lumogen® F Violet 570 and Lumogen® F Yellow 083 as well as a combination of both yields improvements for Cu(In,Ga)Se₂ solar modules. Particularly, we find that the short circuit current density of a Cu(In,Ga)Se₂ mini-module is improved by 1.5 mA cm^− 2 when applying a varnish with a combination of Lumogen® F Violet and Yellow. About 0.5 mA cm^− 2 of this improvement is due to a reduced overall reflectance and an improvement of 1 mA cm^− 2 results from the frequency conversion by the dyes.     

Reversible changes of the fill factor in the ZnO/CdS/Cu(In,Ga)Se2 solar cells

The reversible persistent changes of the fill factor (FF) induced by the illumination and voltage bias along with changes in the electronic properties of the ZnO/CdS/Cu(In,Ga)Se₂ photovoltaic devices have been studied. Admittance spectroscopy and capacitance–voltage characterization reveal a correlation between the FF and the space charge distribution within the absorber. Our experiments provide evidence that a major source of FF loss in efficient devices is caused by excess negative charge close to the interface. We explain the persistent changes in the net acceptor concentration in the interface region by the relaxation effects due to compensating donors—the same mechanism, which leads to metastable changes of the doping level in the bulk of the absorber.     

Epitaxial growth of GaN on (0001) Al<Subscript>2</Subscript>O<Subscript>3</Subscript> via solution-cast seed layer formation process using Ga(mDTC)<Subscript>3</Subscript>

This paper reports an alternative method for the growth of GaN epitaxial layer on (0001) Al₂O₃ substrate by hot-wall vapor phase epitaxy technique. Tris (N,N-dimethyldithiocarbamato)-gallium (III), Ga(mDTC)₃ was introduced as a precursor material for the seed layer formation in the growth of GaN. Optimal growth conditions with seed layers formed by the Ga(mDTC)₃ concentration of 0.047 mol/L were identified: Growth temperature was found to be 850 °C, and optimal distance between the reactant outlet and substrate was determined to be 12.5 cm. Characterization results showed that this growth method produce high-crystallinity GaN epitaxial layers at a relatively lower growth temperature compared to the existing growth techniques and simplify the growth process.     

应用光度分析法测定铁和渣中的微量镓

用光度分析法测定镓，为适应多种试样的测定，补做了个别条件试验。用该方法测定了铁、渣、浸钒渣等六种不同类型试样中镓的含量，分析其精度精度符合要求。     

用熔融还原的方法从浸钒渣中提镓——碳饱和情况下的熔融还原过程

用通用旋转组合设计的方法得到了浸钒渣在饱和碳的熔融还原过程中镓的还原提取率与温度,时间及CaO的加入量关系的非线性数学模型。用非线性优化的方法并综合考虑Fe,Mn的回收,得到了最优的工艺条件及结果;用Langmuir—Knudsen方程推算了镓在铁液中的理论挥发量与时间的关系,与由本模型得到的关系式是一致的。