Investigation Of GaN-based Edge-emitting Laser Diodes

The lasing wavelength of GaN-based semiconductor laser diodes can cover the visible region from 200 nm to 365 nm.Besides,researchers focus on ultraviolet laser diodes(UV-LDs)and blue laser diodes because of wide applications in data storage,optical communication,water purification,lithography,and biochemical analysis for UV-LDs and the indispensability in full-color displays for blue LDs.Utilizing GaN-based materials to fabricate semiconductor laser diodes would suffer from numerous difficulties such as p-type doping,strong spontaneous polarization effects in AlGaN materials,electron leakage and low hole injection in the active region.In this paper,the simulation software named PICS3D is used to simulate physical property and optimize the structure of GaN-based edge-emitting semiconductor laser diodes in order to solve problems mentioned above.The main contents are as follows:1)The research progress,the working principle,and main characteristics of semiconductor laser are introduced.Next,the physical model and calculation process used in the calculation of the edge-emitting semiconductor laser diode using PICS3D are introduced.2)Using PICS3D to simulate the physical property of UV-LDs and to construct different structures to investigate the effect on thickness and layer numbers of last quantum barrier(LQB)for UV-LDs’ performance.The calculation results show that UV-LD with 5-layer LQB and thickness of 10 nm is superior to the traditional structure in terms of threshold current,output power,slope efficiency and optical confinement.In addition,this structure can effectively suppress the leakage of carriers from active region and enhance stimulated radiation recombination.3)Using PICS3D to simulate three kinds of blue-violet LDs with different cavity length and ridge width.The cavity length contains 800μm and 1000μm,the ridge width contains 15μm and 30μm.Obtaining the data of stimulated radiation distribution,local gain and temperature change to investigate the effect on cavity length variation and ridge width variation for threshold current,thermal property,lasing wavelength and to seek the reason why threshold current changes.