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首页> 外文期刊>Physica Scripta: An International Journal for Experimental and Theoretical Physics >Luminescence of coesite
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Luminescence of coesite

机译：堇青石的发光

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Coesite is a polymorph modification of crystalline silicon dioxide with a tetrahedral structure. The luminescence of a single crystal of synthetic coesite was studied under excitation using x-rays, an electron beam, and excimer lasers KrF (248 nm), ArF (193 nm) and F-2 (157 nm). Luminescence bands in the regions of 2.5 eV and 4.4 eV appear. The blue band is dependent on temperature and is composed of decay kinetics. Three main decay times are revealed, exhibiting luminescence of a different nature in the same range of the spectrum. One is in the ns range of time with a time constant of about 2 ns. The two other decay times are in the regions of 5 mu s and 700 mu s. The 5 mu s component is also seen under KrF excitation, whereas both the 5 mu s and 700 mu s components are seen under ArF excitation. The time resolved spectra are mutually similar and they correspond to those under x-ray and e-beam excitation. The UV band is fast with a time constant of less than 1 ns, independent of temperature. Only the 2 ns and 5 mu s components are revealed for the blue band under the KrF laser excitation. Blue luminescence thermal quenching takes place for temperatures above 50 K, with good correspondence between the intensities of the thermal dependences under different excitation and that of the decay time constant. The quenching parameters used are 0.05 eV of energy and a frequency factor of 6 . 10(5) s(-1). The UV band is practically independent of temperature in the range 10-290 K. The nature of luminescence is ascribed to the coexistence of a host defect and a self-trapped exciton. The defect is similar to the known oxygen-deficient luminescence center in pure silica glass. The blue luminescence at 700 mu s is ascribed to the self-trapped exciton being characteristic of silicon dioxide with a tetrahedral structure.
机译：堇青石是具有四面体结构的结晶二氧化硅的多晶型物修饰。在使用X射线，电子束和准分子激光器KrF（248 nm），ArF（193 nm）和F-2（157 nm）激发的条件下，研究了合成堇青石单晶的发光。出现2.5 eV和4.4 eV区域的发光带。蓝带取决于温度，由衰减动力学组成。揭示了三个主要的衰减时间，在相同的光谱范围内表现出不同性质的发光。一个在ns的时间范围内，时间常数约为2 ns。另外两个衰减时间在5 s和700 s的范围内。在KrF激发下也可以看到5μs的成分，而在ArF激发下可以看到5μs和700μs的成分。时间分辨光谱彼此相似，它们对应于在X射线和电子束激发下的光谱。 UV谱带快速，其时间常数小于1 ns，与温度无关。在KrF激光激发下，蓝带仅显示2 ns和5μs分量。蓝色发光热淬灭发生在50 K以上的温度下，在不同激发下的热依赖性强度与衰减时间常数之间具有良好的对应关系。使用的淬灭参数为0.05 eV的能量和6的频率因子。 10（5）s（-1）。紫外波段实际上不受温度范围10-290 K的影响。发光的性质归因于宿主缺陷和自陷激子的共存。该缺陷类似于纯石英玻璃中已知的缺氧发光中心。 700μs处的蓝色发光归因于自陷激子，该激子是具有四面体结构的二氧化硅的特征。

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