Research On Structure Optimization Of Electrically Pumped AlGaN-based Ultraviolet Laser Diodes

AlGaN-based ultraviolet laser diodes(UV-LDs)have great significance for many fields such as medical diagnosis,biological detection,chemical analysis,non-line-ofsight communication and high-density data storage.Compared with other solid and gas lasers,they have the advantages of high beam quality,high efficiency,low cost,small size,etc.Although there are many researchers dedicated to the research of promoting its performance improvement,the research progress of electric pumped AlGaN-based UV quantum well laser diodes have been relatively slow so far.Because of the poor crystal quality,the difficulty of p-type doping,the low efficiency of carrier injection,and optical confinement issues obstruct the realization of high-performance UV laser diodes at shorter wavelengths.Therefore,it is necessary to carry out structural optimization research on AlGaN-based ultraviolet laser diodes and theoretically explore the method of improving device performance.In this paper,PICS3D software is used for numerical simulation of AlGaN based ultraviolet laser diode and the main work is divided into two parts.The first part is to study the UV-A LD electron blocking layer and a new structure LD using BAIN electron blocking layer(EBL)was proposed.The other part explores the effects of different polarity on the optical,electrical and thermal properties of UV-B LD.The main contents of this article are summarized as follows:First,the development of semiconductor laser,the working principle and basic properties of Ⅲ-nitride materials are briefly summarized.Besides,the research progress and challenges of AlGaN-based UV laser diodes are summarized and analyzed.Then the output function,operation flow and main physical model of PICS3D software are introduced,and the main characteristics of semiconductor laser are discussed.Second,using PICS3D software to optimize the electron blocking layer of the electrically AlGaN-based UV laser diode.First of all,the effect of different Al compositions of AlGaN traditional EBL on the device performance was studied,further a new EBL using BAlN material was proposed.The simulation results show that compared with the traditional structure,the new structure LD using BAIN EBL can effectively block the electron leakage and improve the hole injection efficiency,which promotes the reduction of the threshold current and the improvement of the slope efficiency and the output optical power.Furthermore,the low refractive index BAlN material also enhances the optical field confinement.Third,Based on a review of the development status and potential advantages of N-polar-plane Ⅲ-nitride photoelectric devices,using PICS3D software to construct the different polarities AlGaN UV-B LDs.Through a series of simulation calculations and comprehensive analysis of optical properties,electrical properties and thermal characteristics of LDs of different polarities,the results showed that the threshold current,output power,and laser optical intensity of the N-polar LD are more advantageous than the Ga-polar LD,but the temperature stability is poor.To delve into the reasons found that the reverse polarization electric field of the N-polar LD improves the carrier injection efficiency,which improves the photoelectric performance,while the decrease in thermal resistance causes the device temperature to rise faster.