Fig. 1. Layer structure of the wafer. (a) Schematic of the cross-sectional structure; (b) cross-sectional transmission electron microscopy image of InGaN/AlGaN multiple quantum well active region

Fig. 2. Preparation process and morphology of MR-LED. (a) Schematic illustration of the fabrication; (b) SEM image

Fig. 3. Photoelectric performance of MR-LED. (a) Current-voltage curve of MR-LED, inset shows MR-LED spot driven by 6 mA current; (b) electroluminescence curves of MR-LED

Fig. 4. Electroluminescence spectrum of the LED and the response curve of the LED

Fig. 5. Characterization of communication performance of MR-LED as transmitter. (a) -3 dB frequency response; (b) transmitted and received pseudo-random binary sequence data at transmission rate of 150 Mbit/s; (c) eye diagram at 150 Mbit/s

Fig. 6. Schematic diagram and test result of the optical wireless image transmission. (a) Schematic diagram; (b) eye diagram of the amplified signal; (c) transmitted original image; (d) restored image

Fig. 7. Received signals of MR-LED in different detection modes. (a) Different negative bias voltages; (b) different frequencies of the laser; (c) different forward bias voltages