Structural and luminescence characteristics of CuAlxIn1−xSe2 (0 < x ≤ 0.30) chalcopyrite solid solutions

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Optimized Aluminum Reflector for Enhancement of UVC Cathodoluminescence Based-AlGaN Materials with Carbon Nanotube Field Emitters

The far ultraviolet C (UVC) light sources based on carbon nanotube (CNT) field emitters as excitation sources have become promising light sources for sterilization, disinfection, and water purification. However, the low light extraction efficiency of UVC–CNT light sources still hinders the practical application of these structures. Herein, we report an optimized aluminum (Al) reflector to enhance the light extraction efficiency of UVC–CNT light sources. Optical analysis of UVC-CNT light sources covered by the Al reflectors with various thicknesses ranging from 30 to 150 nm was performed to realize the optimized reflector. The UVC-CNT light sources exhibit the highest light extraction efficiency when the Al reflector layer has an optimized thickness of 100 nm. For comparison, the cathodoluminescence (CL) spectra were recorded for UVC–CNT light sources with and without the optimized Al reflector. The measured light output power and the estimated power efficiency of the UVC–CNT light-source-tube with Al reflector were enhanced by about 27 times over the reference. This enhancement is mainly attributed to the outstanding reflection effect of the Al reflector.     

Cathodoluminescence Response From Sanidine Feldspar

ABSTRACT

In the present study, cathodoluminescence (CL) providing information about surface rather than bulk material reveals blue and red emissions within the sanidine feldspar from the Eifel Mountains, Germany. The emission line occurring in the blue region at about 450 nm reflects Al?O^??Al structural defects, although distribution maps of the major elements, including Si, Al, and K, do not display a clear correlation with the CL properties of the sanidine feldspar. Dominant emission being in the longer-visible wavelength region (red region) ～730 nm is assumed to be caused by Fe³⁺ activation attributed to Fe³⁺?Al³⁺ substitution. Much less is known about the spectral characteristic of the feldspar CL emission, and the application of an older luminescence technique yields encouraging results for the practical application of the feldspar identification.     

Si表面上生长的ZnO薄膜的阴极射线荧光

几种不同温度下退火的用直流溅射法生长的ZnO／Si样品的阴极射线荧光(CL)光谱显示，当退火温度低于等于800℃时，随着退火温度的升高，薄膜的晶体质量得到了改善，这主要体现在390nm紫外带的发射强度与505nm绿带发射强度的相对比值迅速增加，同时也发生了绿带的红移以及窄化效应。但退火温度超过800℃时绿带就不再红移了，其峰值为525nm。当退火温度为950℃时，紫外带几乎消失，而只剩下绿带，且与纯硅酸锌样品的CL谱一致，掠入射X射线衍射测量表明，确有三角相三元化合物硅酸锌的产生。因此，从ZnO／Si异质结的质量来看，直流溅射法可能不适宜用于生长这样的异质结：因为当退火温度低于800℃且相差较大(如600℃)时，不能得到产生强ZnO紫外发光的晶体质量，而当退火温度接近或高于800℃时，虽然zn0晶体质量得到了改善从而紫外发光份额迅速增加，但同时也产生了新的三元化合物硅酸锌，将严重影响ZnO／Si异质结的电学输运特性。     

共轭聚合物MEH-PPV的固态阴极射线发光

在有机／无机异质结ZnS／MEH－PPV／ZnS器件中，交流驱动条件下，实现了共轭聚合物MEH－PPV的固态阴极射线发光，器件的发光光谱与MEH－PPV的光致发光谱相同。电子经过ZnS层加速后，成为过热电子，这些过热电子直接碰撞激发MEH－PPV而发光。在日光灯照明下，可以看到器件的均匀发光。     

阴极荧光光谱有效收集效率的计算与测量（I）

从点光源均匀发光模型出发,重点导出了回转半椭球面镜的阴极荧光(Cathodoluminescence,简称CL)光谱有效收集效率η_λ~(eff)的计算公式,分析讨论了收集效率η_λ~(eff)与椭球参数e、收集角、Δφ出射角Δ(?)以及出射光束方位角θ_N的关系,给出了相应的理论计算和模拟实验结果.研究表明,理论计算与实验结果一致.     

喷雾热解法制备的SrWO4膜的阴极射线发光

利用超声喷雾热解法制备了钨酸锶SrWO₄多晶发光膜,并研究了制备条件及掺杂对其阴极射线发光特性的影响.生成的发光膜在300℃以上退火后具有白钨矿结构,其阴极射线发光为一宽带的蓝光,包括一个位于448nm的蓝色发光带和一个位于488.6nm的蓝绿色发光带,是由阴离子络合物WO₄^2-的电荷转移跃迁引起的.发光强度随着退火温度的升高而增强,而退火气氛对其影响不大.在SrWO₄膜中掺入银离子Ag⁺和镧离子La³⁺后,不影响其发光特性,但铕离子Eu³⁺的掺入对发光特性有影响.     

Cathodoluminescence of Eu2+ in EuGa2S4 and Ga2S3:Eu2O3

We present the results of an investigation of the cathodoluminescence of the Eu²⁺ ion in gallium chalcogenides (Ga₂S₃) and europium thiogallate (EuGa₂S₄). We show that the intense wide-band radiation of these compounds is due to the 4f-5d transitions of the Eu²⁺ ions. With increase in the Eu²⁺ percent composition from 0.1 to 5.0 mol.% the luminescence brightness increases and then decreases. Translated from Zhurnal Prikladnoi Spektrskopii, Vol. 67, No. 2, pp. 268–270, March–April, 2000.     

Photo- and cathodoluminescence of the cetylpyridinium chloride: ZnO nanocomposites

The cathodoluminescence and photoluminescence (PL) spectra of ZnO nanoparticles (NPs) embedded into the cetylpyridinium chloride (CPCL) matrix were studied. The composites were obtained by drying an aqueous suspension of CPCL and ZnO NPs, with NaCl and with NaOH additives. We observed that only NaOH addition lead to a significant increase in the PL intensity which we attribute to the surface chemistry of the ZnO NPs. We propose that thin ZnOH₂ and Na₂ZnO₂ layers form on the surface of the NPs; these layers present an increased number of oxygen vacancies, which act as emitting centres.