Improvement Of Light Transmittance Optimization Of ITO Transparency Electrode Of GaN-LED

Light-emitting semiconductor chip solid material in the semiconductor carrier occurs through release of excess energy complex caused by photon emission.Then the luminescent device of this process is the fourth generation source,which can turn electric power into light energy.Moreover,LED has developed fast and shows its application value in more and more areas,especially in lightning field,disinfect,medical field,printing industry,biochemical detection,optical data storage and secure communication.Because of the big difference of refractive index,substrate and electrode absorb some light,the light extraction efficiency of LED is inefficient.Therefore,improve the light extraction efficiency is important to the production of LED.This text based on the theories of III nitride materials' various characteristics,GaN LED and substrate's fabrication process,ITO transparent electrode's fabrication and testing process.1.This article takes the Membrane absorption principle,Membrane permeability principle and sheet resistance principle as the theoretical basis.Then figure out the film thickness of highest ITO light transmittance in theory.After processing,experiment contiguous film thickness of highest ITO light transmittance.Then draw the bright dipping trend curve of light transmittance and find the film thickness of best light transmittance.Through integrating sphere measurement,light intensity measurement,joule meter measurement and lamp aging test,come to a conclusion about light transmittance can improve 5%when the best ITO film thickness is 500A.2.According to the effect of ITO annealing treatment in material,do the ITO annealing treatment quickly.By means of RTA ITO annealing treatment,perfect the crystal quality of ITO film.Lower the touch voltage and improve the light transmittance.by contact GaN ?.When the environment is nitrogen flow rate is 4.5L/min,the annealing time is 60s and the temperature is 400°C,the effect of RTA is best and the optical power can improve 5%to 10%.3.Wet chemical etching to do the surface treatment of ITO films can improve luminous efficiency and brightness of chip.After 6min 30s of 65 0C concentrated sulfuric acid wet chemical etching 2300A chip,the result of experiment is best and the brightness improve about 5%.