LED with automatic brightness control utilizing the dual function of simultaneous light emission and detection

Abstract

Due to the growing demand for devices supporting the Internet of Things (IoT), it’s necessary to develop integrated chips with small size, fast response and high robustness to provide the application of the IoT. In addition to light emission, GaN-based quantum well diodes (QWDs) can convert light into electricity via the photovoltaic effect, simultaneously exhibiting inherent light emission and detection functionalities. Here, we report a LED with automatic brightness control utilizing the dual function of simultaneous light emission and detection, which is implemented on an III-nitride-on-silicon. Due to the inherent rapid photoelectric conversion of MQW diode, the diode is able to communicate with another. Using one MQW diode as the emitter, and another MQW diode as receiver, a visible light communication link was established. The overlap between the emission and detection spectra demonstrated that simultaneous emission-detection phenomenon also exists in MQW diodes. When the LED is modulated to emit light and we shine it with another modulated light beam at the same time, the LED operates under the simultaneous emissiondetection mode. The MQW diode converted external light into photocurrent as feedback to control circuit, by programming in one-chip computer, we can control the feedback circuit to turn the diode brighter or darker according to our willing. Utilizing the dual function of simultaneous light emission and detection of the MQW diode, the proposed MQW diode on its own can achieve real-time regulation of brightness without an external photodetector by integrating a programmed circuit.