Research On LED Structure And Luminescence Characteristics Of Silicon Based GaN LED

GaN as the third-generation wide-band semiconductor material,due to the adjustable band gap,stable properties and other advantages,can meet the new requirements of modern microelectronics technology for high temperature,high power,high pressure,high frequency and radiation resistance and other harsh conditions.GaN is widely used in photoelectric,power devices and other fields,especially GaN occupies a dominant position in LED lighting and display fields.Although the development of GaN LED materials and devices is quite mature in recent years,from the perspective of integration and sensing applications,GaN LED still has some problems,such as low luminous efficiency and uncontrollable luminous direction,which restricts the potential application of GaN LED.Based on this,this dissertation mainly studies the influence of the structure and size of GaN LED on the luminous performance,the control of radiation direction,and the design and preparation of high-quality resonator led,mainly including the following three aspects:1.Disk and ring devices with different radii were designed and prepared by micro nano processing technology,and the comparative study of variable power electroluminescence spectra was carried out.It was found that the size of inner ring light-emitting devices decreased,the peak center shifted blue,the half height width narrowed,and the luminous efficiency increased;the size of the outer ring light-emitting device becomes smaller,the peak center redshifts,and the half height width becomes wider.The results show that small-size LEDs have better luminous efficiency.The spectral shift of LEDs with different structures may be related to the quantum-confined Stark effect caused by the stress release of the device,this research has reference significance for controlling the luminous wavelength regulation of LED.In order to further improve the luminous efficiency of the microcavity,FIB was used to smooth the side wall of the disk LED device.It is found that the photoelectric properties of the modified devices are decreased,which is due to the physical etching of gallium ions,resulting in the loss of the luminescence properties of the devices.2.In order to make the LED device for directional light output,design and preparation of the wheel with slit of the LED device,the slit design is introduced into the radius of 150 microns wheel device to break the rotational symmetry structure.The experimental results show that the device with slit has narrowed half height width,red shift of peak center and angle resolved electroluminescence.The test shows that the device has the effect of directional radiation,which is verified by COMSOL simulation.It is basically consistent with the experiment,and the radiation direction regulation of LED light is basically realized.In order to further improve the luminous efficiency,the device was suspended.It was found that the luminous intensity of the device increased and the luminous half height width narrowed after suspension,but the volt ampere characteristics were not as good as before suspension,because the corrosive liquid caused damage to the electrode material during suspension.The design of the device is an exploration attempt for3 D LED light-emitting devices,it can be applied to the enhanced focusing of LED devices,which is of great significance for the preparation of high-density photoelectric integrated devices.3.In order to obtain higher spectral quality,a waveguide resonant cavity LED(RCLED)device is designed and prepared.The double waveguide RCLED device is tested and compared with the traditional LED.It is found that there are two strong resonant peaks in the spectrum,the luminous intensity is stronger than the traditional LED,and the variation of peak center and half height width with current is smaller,indicating that the luminescence of RCLED is more stable.Then,the single waveguide RCLED device is tested,The spectrum has a strong luminescence peak at 417 nm,and the minimum linewidth of the spontaneous emission peak is 2.5 nm.Finally,a high-quality luminescence line with narrow linewidth is obtained.This research has important reference significance for the research of RCLED.