Photoelectric Properties And Applications Of InGaN/GaN Quantum Cathode Diodes

Benefiting from the development of semiconductor materials and the innovation of GaN epitaxial growth technology,III-V group GaN-based semiconductor devices have made rapid progress,such as GaN light-emitting diodes(LEDs),photodetectors,lasers,etc.,which have boosted the development of optoelectronic detection and optical communication.LED emitters based on GaN materials,represented by InGaN/GaN MQWs devices,have greater light output efficiency,higher overcurrent capability,and faster switching speed compared to LEDs made of conventional materials.These advantages make it possible to use them in visible light communication and optoelectronic detection.Against this background,this study first prepared InGaN/GaN MQWs devices by using metal-organic chemical vapor deposition(MOCVD)technology,photolithography,and inductive coupled plasma(ICP)etching process on a sapphire substrate to fabricate blue and green light devices of the same size.Secondly,an experimental platform was set up to collect the optical and electrical characteristics of the device,and then the device’s emission spectrum and photodetector spectrum data were analyzed to draw several conclusions.Firstly,the device’s luminous intensity increases with the injection current,making it suitable for use as a light modulator.Secondly,the photodetector spectrum of the device changes with the bias voltage,making it suitable for use as a light demodulator.Thirdly,the emission spectrum and photodetector spectrum of the device overlap,making it possible to use it as both a transmitter and a receiver in optical communication,or as a detector and LED separately.Based on the excellent characteristics of InGaN/GaN MQWs devices,this study designed and fabricated two detection sensing systems using them as photodetectors.The first system is a noncontact elevator sensing control system designed based on the characteristic that only one device is needed to switch between the emitting state and the detection state.This system can be triggered when the passenger’s finger is about 1cm away from the system,and it also has a dual anti-misoperation design,which can effectively reduce the probability of misoperation.The second system is a smoke density detection system designed based on the characteristic that InGaN/GaN MQWs devices can receive light signals from the same structure device.One device is used as a light transmitter and the other device is used as a light receiver.The system can detect the concentration of smoke particles in the air within a certain range,and the error rate is controlled within 5% compared with commercial sensors.In addition,the system integrates the Internet of Things(Io T)technology,and through distributed Io T nodes,the sensing system is connected to form a huge remote fire monitoring system,providing an effective method for disaster prevention and reduction in the future.