An alternative method to fabricate the planar-type resonant-cavity light-emitting diodes by using silicon oxide for short-reach communications

In this article, the silicon oxide (SiO_x) planarization technique is presented to fabricate the 650-nm resonant-cavity light-emitting diodes (RCLEDs). The performances of RCLEDs are characterized by forward voltage, light output power, external quantum efficiency, emission spectrum, and dynamic response. As a result, the device with the SiO_x-planarized layer exhibits a low operating voltage of 2.3 V at 20 mA, a maximum light output power of 304 μW at 15 mA, and the best external quantum efficiency of 3% at 1.2 mA. In addition, the SiO_x-planarized device exhibits temperature insensitivity as compared to the device without it. The RCLED with a 30-μm diameter shows the maximum 3 dB frequency bandwidth of 275 MHz at a driving current of 40 mA. Finally, the RCLED with a SiO_x-planarized layer shows a clear eye-opening feature as operating at 100 Mbit/s at 20 mA. These results indicate that such LEDs are excellent candidates for use in high-speed short-reach plastic optical fiber communications.