Textured V-Pit Green Light Emitting Diode as a Wavelength-Selective Photodetector for Fast Phosphor-Based White Light Modulation

We demonstrate the ability to overcome the slow data transmission of a phosphor-coated white light emitting diode (LED) by replacing a conventional Si photodiode with a narrowband, green InGaN LED as receiver. By relying on the wavelength selectivity of an InGaN LED, we are able to detect the fast blue light components and reject the slow phosphor components from white light illumination, thereby increasing the modulation speed significantly from 5 MHz to 20 MHz. V-pit texturing is used to improve the peak responsivity of InGaN LEDs to 0.23 A/W at 380 nm, which is comparable with the highest values reported in InGaN detectors. Such V-pit structures also help to shield nonradiative recombination at threading dislocations, so that a high breakdown voltage of −40 V with a high bandwidth of 275 MHz can be obtained. This demonstrates the suitability of V-pit textured InGaN LEDs to function not only as a bright emitter but also as a highly responsive, fast photodetector. This dual functionality enables high-spe...