Vertical Structure GaN-based Light-emitting Diode Communication Chip On Si Substrates

LED devices have been widely used in traditional fields such as general lighting and backlight display,and are gradually integrated into intelligent applications.With the continuous development of LED devices,the visible light communication technology based on LED has also become a research hotspot.As a third-generation semiconductor material,gallium nitride has the advantages of big band gap,good stability,and high operating frequency,and has become a key material supporting high-speed information technology.Multiple-quantum-well LED devices based on gallium nitride have functions such as light-emitting and light-detecting,can integrate light-emitting diodes and photodetetctor in one chip,and provide new solutions for the development of visible light communication.In this work,the ultra-thin LED chip is designed on a vertical structure Ga N-on-silicon wafer,and fabricated via thining-etching without hard mask process,photolithography process,ICP etching,electron beam evaporation and rapid annealing proess.The vertical structure LED chip has the advantages of high power and high light efficiency,which is beneficial to the transmission of optical signals in the communication system.The external appearance of the prepared LED chip is characterized by scanning electron microscope,optical microscope and atomic force microscope(AFM).The picture of AFM shows the thickness of the LED epitxial film at 225 nm,which effectively suppressed the lateral waveguide transmission mode of the LED chip.At the same time,the highly reflective silver mirror under the p-Ga N layer also improved the light extraction efficiency of the LED.The photoelectric characteristics of LED chip,such as current voltage curve,capacitance voltage curve,detection spectrum and EL spectrum,are measured by Semiconductor parameter analyzer.The result shows that there is an overlap of ?25nm between the EL spectrum and detection spectrum of LED chip.Based on the overlap of the emission spectrum and detection spectrum of the vertical strcucture ultra-thin LED chip,an out-of-plane light communication system was established.When the LED chip is used as a light-emitting diode,the external photodetector receives the transmitted signal of the LED chip and the communication rate can reach 10 Mbps.When the LED chip is used as a light detection device,it can receive an external light source signal rate of 5Mbps.When the LED chip transmits the light signal and receives the signal from the external light source,a superimposed signal of two different frequency signals is generated on the LED chip,which verifies that the multiple-quantum-well LED chip has Simultaneous light-emitting light-detecting function,and provides the chip foundation for full duplex communication.