新型可溶性酞菁的合成和光致发光及电致发光性质

以3(4)-硝基邻苯二腈和对甲氧基苯酚为原料, 经过两步反应合成了α(β)-四(4-甲氧基苯氧基)酞菁锌, 通过谱学方法和元素分析表征了其结构. 比较研究其溶液和旋涂膜的紫外可见光谱、光致发光光谱和固体薄片的光致发光光谱. 并以其旋涂膜为发光层制备了电致发光器件, 研究其电致发光性质. 结果表明, 固态酞菁材料与其溶液的荧光发射波长相比均向长波方向移动了145 nm以上, 而且都有不同程度的宽展. 在固态下β-位取代酞菁荧光发射波长红移的程度比α-位取代酞菁大. 电致发光光谱的发射波长和其旋涂膜的光致发光光谱的发射波长基本一致, 大约在856和862 nm左右. 在固态下酞菁分子排列紧密, 分子间相互作用增强导致了荧光发射波长的巨大红移.     

Photoluminescence and X-Ray Photoelectron Spectroscopy of p-Type Phosphorus-Doped ZnO Films Prepared by MOCVD

Reproducible p-type phosphorus-doped ZnO （p-ZnO：P） films are prepared on semi-insulating InP substrates by metal-organic chemical vapour deposition technology. The electrical properties of these films show a hole concentration of 9.02 × 10^17 cm ^-3, a mobifity of 1.05 cm^2 /Vs, and a resistivity of 6.6 Ω.cm. Obvious acceptorbound-exciton-related emission and P-induced zinc vacancy （Vzn） emission are observed by low-temperature photoluminescence spectra of the films, and the acceptor binding energy is estimated to be about 125meV. The local chemical bonding environments of the phosphorus atoms in the ZnO are also identified by x-ray photoelectron spectra. Our results show direct experimental evidence that Pzn-2Vzn shallow acceptor complex most likely contributes to the p-type conductivity of ZnO：P films.     

SiN插入层对GaN外延膜应力和光学质量的影响

研究了MOCVD系统中原位SiN插入层对GaN薄膜应力和光学性质的影响。采用SiN插入层后,GaN薄膜的裂纹数量大大减少,薄膜所承受的张应力得到了一定的释放。同时,GaN薄膜的缺陷密度降低一倍,晶体质量得到了极大的改善。研究表明,位错密度的降低在GaN薄膜中留存较大的残余应力,补偿了降温过程中所引入的张应力。同样,随着SiN插入层的应用,低温PL谱的半峰宽降低,薄膜光学质量提高。最后研究了PL谱发光峰与应力的关系,得到了一个-13.8的线性系数。     

On the fluorescence enhancement mechanism of Er3+ in germanate glass containing silver particles

The spectral properties of trivalent erbium ions(Er3+) are systematically studied in a melt-quenched germanate glass(60 GeO2-20PbO-10BaO-10K2O-0.1Ag2O) containing silver(Ag) particles.Thermal treatment of the material leads to the precipitation of Ag particles as observed by transmission electron microscopy and confirmed by absorption spectrum for the obvious surface plasmon resonance peak of Ag particles.The fluorescence from Er3+ in the 10-min-annealed sample with Ag particles is found to be 4.2 times enhanced compared with the unannealed sample excited by 488-nm Ar+ laser.A comparison is made between a spectral study performed on the unannealed Er3+-doped sample and the one annealed for 20 min.The data of absorption cross section and Judd-Ofelt intensity parameters show the agreement between the two samples no matter whether there are Ag particles,indicating that the introduction of Ag particles by post-heat treatment has no effect on the crystal field environment of Er3+ ions.The fluorescence enhancement is attributed to the surface plasmon oscillations of Ag particles in germanate glass.     

400nm高性能紫光LED的制作与表征(英文)

利用金属有机物化学气相沉积技术在蓝宝石衬底表面制备了带有p-AlGaN电子阻挡层的400 nm高性能紫光InGaN多量子阱发光二极管。制作了3种紫光LED,分别带有不同p-AlGaN电子阻挡层结构:Al摩尔分数为9%的p-AlGaN电子阻挡层;Al摩尔分数为11%的p-AlGaN电子阻挡层;Al摩尔分数为20%的10对p-AlGaN/GaN超晶格电子阻挡层。带有高浓度Al电子阻挡层的紫光LED的光输出功率高于低浓度Al电子阻挡层的紫光LED。带有10对p-AlGaN/GaN超晶格电子阻挡层的紫光LED的光输出功率获得了极大的提高,在20 mA注入电流时测试得到的光输出功率为21 mW。此外,该LED同时显示了在高注入电流下接近线性的I-L特性曲线和在LED芯片表面均匀的发光强度分布。     

衬底弯曲度对GaN基LED芯片性能的影响

利用低压MOCVD系统在弯曲度值不同的蓝宝石衬底上生长了GaN基LED外延结构并制作芯片。测量了芯片的主要电学和光学参数,并分析了衬底弯曲度值对芯片性能的影响。分析结果表明:存在弯曲度的衬底预先弛豫了外延层中的部分应力,改善了外延层的质量,从而提高了LED芯片的性能。随着衬底弯曲度值的逐渐增加,下层GaN对有源层中InGaN材料的压应力作用不断减小,导致芯片的主波长逐渐发生蓝移。     

喷淋头高度对InGaN/GaN量子阱生长的影响

在Aixtron 3×2近耦合喷淋式金属有机化学气相沉积反应室中,调节喷淋头与基座之间的距离,制备了7,13,18,25 mm间距的4个InGaN/GaN量子阱样品。利用原子力显微镜(AFM)、X射线衍射(XRD)对样品表面形貌及界面质量进行了表征。研究表明:随着高度的增加,量子阱的表面粗糙度减少,垒/阱界面陡峭度逐步变差,垒层和阱层厚度及阱层In组分含量减少;增加高度至一定值后,量子阱厚度及In组分趋于稳定。此外,对比垒层和阱层的厚度变化,垒层厚度的变化幅度较阱层更为明显。     

石英光纤的金属镍锡涂敷工艺研究

为了实现石英光纤传感器的无胶金属化封装,需要在光纤表面涂敷金属层。先利用化学镀方法在石英光纤表面镀镍层,再利用电镀工艺电镀锡层,从而获得表面光亮、均匀、附着牢固、可焊性好的金属涂敷层。实验中研究了敏化、活化工艺对镀层的影响并提出一种效果较好的敏化活化方法。给出了石英光纤表面化学镀镍的最佳工艺条件。     

Enhanced Output Power of Near-Ultraviolet Light-Emitting Diodes by p-GaN Micro-Rods

Near-ultraviolet （UV） InGaN/AIGaN light-emitting diodes （LEDs） are grown by low-pressure metal-organic chemical vapor deposition. The scanning electronic microscope image shows that the p-OaN micro-rods are formed above the interface of p-A1GaN//p-OaN due to the rapid growth rate of p-OaN in the vertical direction. The p-OaN micro-rods greatly increase the escape probability of photons inside the LED structure. Electrolumi- nescence intensities of the 372nm UV LED lamps with p-OaN micro rods are 88% higher than those of the i/at surface LED samples.