GaN-based mid-power flip-chip light-emitting diode with high -3  dB bandwidth for visible light communications

By directly flip-chip soldering three mid-power light-emitting diode (LED) chips with periodic micro-via-holes on ceramic substrates, -3  dB modulation bandwidths of 49.9 MHz, 58.8 MHz, and 25 MHz are obtained at the driving current of 170 mA. To the best of our knowledge, these are the reported highest -3  dB bandwidth values for flip-chip power-type LEDs (FC-LEDs) at the low-bias current levels. Moreover, good radiant powers are also achieved: 180.2 mW, 168.8 mW, and 233.8 mW at 150 mA, respectively. With a gold wire-free feature, the fabricated FC-LEDs could offer an opportunity to miniaturize the package volume of a LED module for illumination and free-space high-speed VLC dual-usage applications.