| Abstract: | The thermal-electrical characteristic of a GaN light-emitting diode(LED) with the hybrid transparent conductive layers(TCLs) of graphene(Gr) and NiO_x is investigated by a finite element method.It is indicated that the LED with the compound TCL of 3-layer Gr and 1 nm NiO_x has the best thermal-electrical performance from the view point of the maximum temperature and the current density deviation of multiple quantum wells,and the maximum temperature occurs near the n-electrode rather than p-electrode.Furthermore,to depress the current crowding on the LED,the electrode pattern parameters including p- and n-electrode length,p-electrode buried depth and the distance of n-electrode to active area are optimized.It is found that either increasing p- or n-electrode length and buried depth or decreasing the distance of n-electrode from the active area will decrease the temperature of the LED,while the increase of the n-electrode length has more prominent effect.Typically,when the n-electrode length increases to 0.8 times of the chip size,the temperature of the GaN LED with the1 nm NiO_x/3-layer-Gr hybrid TCLs could drop about 7K and the current density uniformity could increase by23.8%,compared to 0.4 times of the chip size.This new finding will be beneficial for improvement of the thermalelectrical performance of LEDs with various conductive TCLs such as NiO_x/Gr or ITO/Gr as current spreading layers. |
