Study on Low Voltage Direct Current Electroluminescence Characteristics in ZnS/Si Hetero-junction Device and Related Fluorescent Materials

研究了ITO/ZnS：Mn/n-Si异质结器件的电致发光特性。器件在电成型处理后显示出电致发光。器件在室温下以直流电模式稳定工作，发光起始电压可降低到7[V]左右。然而，亮度很低。研究结果表明，发光图案是由多个小尺寸发光点组成的集合，这些点的分布取决于成型工艺。这些点的亮度随着施加电压的增加而增加。然而，这些点的数量并不随电压的增加而变化，并且这些点的数密度很低。因此，亮度没有达到实用价值。我们进一步研究了不同结构的器件：ITO/ZnS：Mn/p-Si、ITO/ZnS：Mn/Y2O3/n-Si或ITO/ZnS：Mn/ZnO/n-Si，以及激光辐照硅表面对提高发光亮度的影响。作为这些研究的结果，我们观察到，在ZnS：Mn薄膜和Si衬底之间插入取向的氧化锌晶须的器件表现出了良好的电致发光特性。我们将在未来对该装置进行研究。

We studied on the electroluminescence characteristics of the ITO/ZnS:Mn/n-Si hetero-junction devices. The devices show the electroluminescence after the electrical forming treatment. The devices operate stably with direct current mode in room temperature and we could lower the initiating voltage of luminescence to about 7[V]. The brightness, however, is low. The result of this study has proved that the luminescence pattern is a set of the many small-sized luminescent points and that the distribution of these points is decided at the forming treatment. The luminance of these points increases with the increasing applied voltage. The number of these points does not change with the increasing voltage, however, and the number density of these points is low. Thus the brightness does not reach the practical value. It is necessary to investigate the mechanism of the generation of the luminescence point and to increase the density of the point.Further, we studied on the devices with the different structures; ITO/ZnS:Mn/p-Si, ITO/ZnS:Mn/Y2O3/n-Si or ITO/ZnS:Mn/ZnO/n-Si, and on the effect of the Nd:YAG laser irradiation on the Si surface to increase the brightness. As the results of these studies we observed that the device with the inserted layer of the oriented ZnO whiskers between the ZnS:Mn film and the Si substrate showed the excellent electroluminescence characteristics. We study on this device in the future.