Influence of ITO,Graphene Thickness and Electrodes Buried Depth on LED Thermal-Electrical Characteristics Using Numerical Simulation

Finite elements methods are used to investigate the thermal-electrical characteristics of gallium-nitride （GaN） light-emitting diodes （LEDs） with different transparent conductive layers （TCLs） and buried depths of electrodes, where the transparent conductive layers include indium tin oxide （ITO）, graphene （Gr） and the combination of them （ITO/Gr）. The optimal material parameters and the precision and accuracy of the simulation model are validated. Moreover, the parameters＇ sensitivity analysis is carried out as well. The results indicate that the LED with the TCL of a lO0-nm ITO or 4-1ayer Gr has a good thermal-electrical performance from the viewpoint of the maximum temperature and the current density deviation of multiple quantum well （MQW）, where the maximum temperature occurs at the n-Pad rather than p-Pad. The compound TCL with a 20-nm ITO and 3- layer Gr reaches a thermal-electrical performance better than that of a lO0-nm ITO or 4-layer Gr. Moreover, their maximum temperatures decrease about -0.43% and 1.21%, and the current density uniformities increase up to -6.09% and 17.41%, respectively. Furthermore, when the electrode buried depth is 0.51 μm, the thermal-electrical performance of the GaN LEDs can be further improved.     

智能金属结构中光纤光栅传感器的无粗化镀膜工艺

为了用金属直接固化代替目前的环氧粘接技术,从而实现光纤光栅传感器的无胶粘接,提出了一种无需粗化的光纤光栅传感器表面金属化工艺方法,并通过化学镀镍磷(Ni-P)合金,实现了光纤传感器的金属化封装。采用扫描电子显微镜、能谱仪、X射线衍射仪及热振试验分别对涂层的表面形貌、成分、结构和结合力进行了检测和分析,结果表明,制备所得涂层表面光滑、平整且致密;同时,通过镀膜光纤光栅传感器件与金属构件的实际键合试验,证明其结合力强、力学性能良好,能满足光纤光栅传感器的使用要求。