Optical, spectral, and thermal characteristics of InGaN/GaN green flip-chip light-emitting diodes

We reported the temperature-dependent device characteristics of InGaN/GaN green flip-chip light-emitting diodes (large chip size of 1125 × 1125 μm²) on patterned sapphire substrate. Through the experiments in the temperature range of 298-358 K, optical, electrical, and spectral properties were measured and analyzed. At 350 mA and 298 K, the optical output power of 56.2 mW, forward voltage of 3.26 V, and emission peak wavelength of 503.6 nm were obtained. The characteristic temperature was also estimated at an injection current of 350 mA under pulsed mode, indicating a value of 1019 K. The junction temperature was experimentally measured by the forward voltage method. For comparison with theoretically calculated results, three-dimensional steady-state heat transfer model based on finite element method was employed. The thermal resistance (∼ 12.76 K/W) extracted from the experimental results exhibited a similar value with the simulated result (∼ 14.22 K/W).