利用磁控溅射在GaN/蓝宝石衬底上生长ZnO薄膜

Zinc oxide (ZnO) thin films were grown on n-GaN/sapphire substrates by radio-frequency (RF) magnetron sputtering. The films were grown at substrate temperatures ranging from 400 to 700 ℃ for 1 h at a RF power of 80 W in pure Ar gas ambient. The effect of the substrate temperature on the structural and optical properties of these films was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) spectra. XRD results indicated that ZnO films exhibited wurtzite symmetry and c-axis orientation when grown epitaxially on n-GaN/sapphire. The best crystalline quality of the ZnO film is obtained at a growth temperature of 600 ℃. AFM results indicate that the growth mode and degree of epitaxy strongly depend on the substrate temperature. In PL measurement, the intensity of ultraviolet emission increased initially with the rise of the substrate temperature, and then decreased with the temperature. The highest UV intensity is obtained for the film grown at 600 ℃ with best crystallization. oindent     

Design and optimization of a monolithic GaInP/GaInAs tandem solar cell

We have theoretically calculated the photovoltaic conversion efficiency of a monolithic dual-junction GaInP/GaInAs device,which can be experimentally fabricated on a binary GaAs substrate.By optimizing the bandgap combination of the considered structure,an improvement of conversion efficiency has been observed in comparison to the conventional GaInP_2/GaAs system.For the suggested bandgap combination 1.83 eV/1.335 eV,our calculation indicates that the attainable efficiency can be enhanced up to 40.45%(30...     

石墨上多晶硅薄膜的制备及择优取向的调控

利用磁控溅射在石墨衬底上制备了非晶硅薄膜,并使用快速热退火对薄膜进行了晶化处理。XRD分析表明,直接溅射沉积在石墨衬底上的硅薄膜经过快速热退火后具有高度的(220)择优取向。通过在硅薄膜和石墨衬底界面处引入一定厚度的ZnO中间层,晶化后的多晶硅薄膜择优取向实现了从(220)向(400)的转变,从而非常有利于将成熟的制绒工艺应用于该材料体系的电池制备过程中。对于择优取向的转变提出了解释,认为Si(100)面和ZnO(001)面晶格匹配是主要原因。喇曼分析表明ZnO中间层的引入提高了多晶硅薄膜的晶体质量。     

Ag颗粒表面等离子体增强GaAs太阳电池双层减反射膜的设计与模拟

Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically.The reflectance of double-layer antireflection coatings（ARCs） with different suspensions of Ag particles is calcu-lated as a function of the wavelength according to the optical interference matrix and the Mie theory.The mean dielectric concept was adopted in the simulations.A significant reduction of reflectance in the spectral region from 300 to 400 nm was found to be beneficial for the design of ARCs.A new SiO2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.     

铝诱导多晶硅薄膜籽晶层的电学性质

利用磁控溅射系统在玻璃衬底上制备出具有玻璃∕铝∕非晶硅的多层膜结构样品,然后在管式退火炉中以一定的温度退火,使非晶硅晶化形成多晶硅薄膜籽晶层。扫描电子显微镜(SEM)及光学显微镜测试表明,铝诱导结晶后样品中的铝层已被完全置换为连续并且厚度均匀的多晶硅层,多晶硅晶粒的平均尺寸为23μm。喇曼光谱测试和X射线衍射(XRD)分析表明,多晶硅薄膜籽晶层具有良好的结晶质量,并且具有高度的(111)择优取向。霍尔测试结果表明,铝诱导多晶硅薄膜籽晶层属于高浓度p型掺杂,掺杂浓度达到了1018/cm3。分析认为铝在非晶硅晶化过程中不仅扮演了诱导金属的角色,还起到了掺杂的作用。     

GaInP/GaInAs 叠层太阳电池的结构设计及优化

我们计算了单级联GaInP/GaInAs叠层太阳能电池理论转换效率,在实验上它通常生长在GaAs衬底上。相比于传统的GaInP2/GaAs叠层电池,通过对禁带宽度组合的优化,我们得到了更高转换效率的体系结构。这里,对于所考虑禁带组合1.83eV/1.335eV,计算结果表明,当对其结构进行优化后（即顶电池GaInP厚度为1550nm,底电池GaInAs厚度为5500nm),其理论转换效率可以达到40.45% (300suns,AM1.5d),另外鉴于它相对于GaAs衬底较低的晶格失配（0.43%),在未来它将更具有应用前途。     

高压GaAs微型太阳电池阵列的制备

为了提高GaAs微型太阳电池的输出性能,对微型太阳电池阵列的主要工艺进行了研究和改进。通过对帽层、背电极层和台面的选择性/非选择性湿法腐蚀工艺的探索,实现了对最佳腐蚀液的配比、腐蚀时间和温度的控制。采用侧壁钝化工艺和聚酰亚氨(PI)/SiO2/TiAu/SiO2新型互连结构,不仅确保了电池单元之间有效的隔离和互连,而且极大地降低了侧壁载流子复合电流,同时这种新型互连结构可有效防止由于衬底光敏现象引起的漏电流。经过上述器件工艺改进,获得了高集成度GaAs微型太阳电池阵列。电流-电压(JSC-VOC)测试结果显示,器件的开路电压达到84.2V,填充因子为57%。     

Enhancement of light trapping in thin-film solar cells through Ag

Forward-scattering efficiency (FSE) is first proposed when an Ag nanoparticle serves as the light-trapping structure for thin-film (TF) solar cells because the Ag nanoparticle’s light-trapping efficiency lies on the light-scattering direction of metal nanoparticles.Based on FSE analysis of Ag nanoparticles with radii of 53 and 88 nm,the forward-scattering spectra and light-trapping efficiencies are calculated.The contributions of dipole and quadrupole modes to light-trapping effect are also analyzed quantitatively.When the surface coverage of Ag nanoparticles is 5%,light-trapping efficiencies are 15.5% and 32.3%,respectively,for 53and 88-nm Ag nanoparticles.Results indicate that the plasmon quadrupole mode resonance of Ag nanoparticles could further enhance the light-trapping effect for TF solar cells.