Simulation Research On Epitaxial Structure Of AlGaN Semiconductor Laser

AlGaN-based deep ultraviolet semiconductor lasers have huge application markets,such as chemical analysis,medical diagnostic equipment,biological reagent detection systems,high-density data storage,water purification and material processing.AlGaN has a relatively wide band gap.By adjusting the content of Al in AlGaN,the laser can radiate in the deep ultraviolet band(<280nm).In recent years,AlGaN deep ultraviolet semiconductor lasers have attracted strong research interest from domestic and foreign research institutions and scholars.However,due to the limitations of epitaxial growth technology,it is difficult to obtain high-quality AlGaN materials.The high activation energy of Mg dopants causes low P-type doping efficiency.The large electron leakage and relatively low hole injection efficiency lead to poor performance.It seriously affects the realization of the superior performance of AlGaN-based deep ultraviolet semiconductor lasers.This thesis focuses on improving the performance of deep ultraviolet semiconductor lasers and optimizes the laser epitaxial structure.The main research contents and innovations of this paper are as follows:1.To reduce the electron leakage of deep ultraviolet semiconductor lasers and increase the carrier radiation recombination rate,an optimized scheme of doubletapered electron blocking layer was proposed.Through the simulation experiment,the differences of three different types of electron blocking layers,namely reference,tapered and inverse tapered,were simulated.The design of double-tapered electron blocking layer was proposed for the first time.Then,a comparative experiment on the energy band,carrier concentration,radiation recombination rate and leakage current of the double-tapered and reference electron blocking layer is designed.Based on the simulation data,it is found that when the laser adopts a double-tapered electron blocking layer,a higher electron potential height can be formed.It can effectively reduce the electron leakage of the laser and increase the carrier radiation recombination rate by 4.9%.2.Due to increase the carrier radiation recombination rate in the active region,this paper proposes the design of a step-like quantum barrier.The simulation results show that the use of a step-like quantum barrier in the laser can effectively improve the carrier radiation recombination rate and slope efficiency.Then,when the step-like quantum barrier is used in the active region,the performance of four different types of electron blocking layers of reference,tapered,inverse tapered and double-tapered is used.Simulation experiment data shows that the double-tapered electron blocking layer still has the best effect in improving the laser carrier radiation recombination rate.Through numerical simulation,the output characteristics of the laser based on the number of different quantum wells are compared.It is found that when the double quantum well structure is used in the laser active region,the internal gain of the laser is the largest and the performance is the best.The optimization of the epitaxial structure of the deep ultraviolet semiconductor laser proposed in this paper which has great significance for improving the electron leakage of the laser and increasing the carrier radiation recombination rate.