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For the study of the performance enhancement of a galliumnitride-based flip-chip light-emitting diode with through-via structure (FC-LED), FC-LED and conventional high-power light-emitting diode (HP-LED) were fabricated simultaneously with the same epitaxial structures and packaging processes. The optoelectronic results showed that the FC-LED's performance of the multiple indices for radiant light and voltage parameters were, respectively, better than that of the conventional HP-LED. One reason for this was that the thermal resistance of the FC-LED chip was about 54% lower, which would induce less heat-flux generation. This was in accordance with the simulation results of the p-n junction temperature. Another reason for this was that the extra parasitic resistance in the conventional HP-LED chip would cause higher voltages and lower multiple indices of radiant power.

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The heat centralization of high power light emitting diode becomes a challengeable issue by reason of the strong relationship between device reliability and operating temperature. The purpose of this work is to study the thermal behavior of light emitting diode device with graphene film transferred to the substrate surface. The experiment results show that junction temperature of the device with graphene film transferred to the alumina ceramic substrate surface is about 2.2°C lower. And the thermal resistance is low by 3.11 K/W compared to that of normal device. It is validated that graphene film can improve the thermal conductivity ability of the alumina ceramic substrate. Accordingly, the results are helpful in enhancing the performance and reliability of high power light emitting diode.