Research On DBR Cavity Structure Of 270nm AlGaN-based Deep Ultraviolet Laser

The development of science and technology is closely related to people’s needs.The development of science and technology continues to meet people’s needs,and people’s demands are also promoting the development of science and technology.Due to the narrow band gap of the first two generations of semiconductor materials,the wavelength cannot be adjusted,and the output power is lower.As a result,they cannot meet people’s needs.The third generation of semiconductors has gradually developed.Because of their unique properties:long service life,the small divergence angle,high light output efficiency,etc.,deep ultraviolet semiconductor lasers have attracted strong interest from domestic and foreign scientific research institutions,enterprises and schools.The material of the deep ultraviolet semiconductor laser is mainly a ternary compound composed of Al N and Ga N.By adjusting the Al composition,the band gap of the material can be varied and the emission wavelength covers the ultraviolet and deep ultraviolet wavelength.This article mainly studies the deep ultraviolet semiconductor laser with 270nm emission wavelength.It is widely used,ranging from military field,medical treatment,communication and other fields,to water purification,optical disk storage,laser printing,and so on.We can say that the deep ultraviolet semiconductor laser has a broad application prospect.This article first introduces the research background of the laser and the importance of the third generation Ga N-based laser at home and abroad,pointing out the direction for the research.Secondly,it introduces the luminescence principle of the semiconductor laser,the material characteristics and the models used by the laser.Subsequently,the software and numerical calculations used for laser simulation are also introduced,and the theoretical preparation for laser structure optimization is completed.Finally,based on the F-P cavity laser,the DBR cavity of the laser is designed.Through the comparison,it can be proved that its electrical characteristics have been significantly improved.In order to contrast with the laser of the DBR cavity,the reference semiconductor laser structure designed in this paper is a ridge type double heterojunction device structure,and the resonant cavity is F-P.Compared with a simple double heterojunction,the divergence angle of the ridge type double heterojunction laser is proved small,and concentrated energy.Secondly,optimize the various layers of the device.The two-layer quantum well not only achieves high-gain stimulated radiation,but also satisfies that the laser will not achieve the gain saturation or thermal effect;the optimization of the thickness of the confinement layer avoids the radiation recombination mainly concentrated in the quantum well near the p-type layer,making the light field more uniformly distributed in the active region;The optimization of the waveguide layer can better confine the light in the active region.The optimized simulation based F-P cavity-based laser has a threshold current of 31.55m A and a slope efficiency of 2.4W/A.This paper proposes to replace the F-P cavity with a DBR cavity,and to design and optimize a laser based on the DBR cavity.The material of DBR is7)/7)_0.65(6_0.35,which improves the interference of light through high and low refractive index.The number of quantum wells increases,the carrier concentration in the active region increases,and the output power increases.The number of cycles increases,the reflectivity of light increases.The waveguide layer is7)_0.64(6_0.36,and the thickness is 10nm.As a result,the threshold current is 11m A,and the slope efficiency is 2.4765W/A.In a conclusion,the electrical performance of DBR laser is better than F-P laser,and its length of resonant cavity is far shorter than F-P cavity.