Quantum Well Structure Of UV-LED Based On Group ? Nitrides

In recent years,group ? nitride semiconductor materials have played an increasingly important role in many aspects.In more and more fields,semiconductor lighting technology represented by GaN-based blue light,white light LED and UV LED is triggering a new technological revolution.However,the luminous efficiency of UV LED is still relatively low,and there are a lot of problems that have not been solved,such as serious electron leakage,low hole injection efficiency,low internal quantum efficiency,and other factors that have limited the further development of UV LED devices.In this paper,the quantum well structure of UV LED and deep UV LED is studied.By adjusting the calculation parameters of APSYS simulation software,a new type of quantum well structure is proposed in a deep ultraviolet band.Which is called the single side inverted triangle structure at the bottom of the well.A novel quantum well structure,the inverted triangle structure at the bottom of the well,is proposed and experimentally verified in the ultraviolet band.Firstly,the development prospect and future market of UV LED are briefly described,and the research status and existing problems of UV LED at home and abroad are introduced.Then,this paper briefly introduces the structure of UV LED quantum well,the principle of luminescence,the basic characteristics of group ?-nitrides,the influence of polarization effect on group ?-nitrides,and the calculation method of APSYS simulation software.For the research of Al GaN based deep UV LED quantum well,three kinds of LED devices with different quantum well widths are constructed by APSYS software.The quantum well widths of the three structures are 2 nm,4 nm,and 6 nm respectively.The simulation results show that the device has the best performance when the width of the quantum well is 4 nm and the width of the quantum barrier is 12 nm.With this well barrier ratio as the basic structure,five kinds of LED with different quantum well structures are designed.Structure A is a traditional structure,structures B and C are single side left gradient and single side right gradient inverted triangle structures,structure D and structure E are single sides left and single side right inverted triangle structures at the bottom of the well.The simulation results show that structure E has the best photoelectric performance.For the research of GaN-based UV LED quantum well,three kinds of LED devices with different quantum well widths are constructed by using APSYS software.The quantum well widths of the three structures are 2 nm,3 nm,and 4 nm respectively.It is found that the device has the best performance when the equivalent quantum well width is 3 nm and the quantum barrier width is 12 nm.In this paper,it is used as well barrier ratio and three kinds of LED with different quantum well structures are designed: structure A is the traditional rectangular quantum well structure;structure B is the triangular quantum well structure;structure C is the inverted triangular quantum well structure at the bottom of the well.Through the simulation of these three structures,it is found that structure C has excellent photoelectric performance.In order to verify the new quantum well structure in the experiment,UV LED with inverted triangle quantum well structure was grown by metalorganic chemical vapor deposition(MOCVD).Through the variable temperature PL test on the grown sample,it is found that when the temperature is 300 K,the luminous intensity of the new structure is greatly improved compared with the traditional structure.In the temperature range of 77 K to 300 K,the luminescence intensity of the new structure is always better than that of the traditional structure.Through the analysis and calculation of the test data after the convection plate,it is found that the output power of the new structure is 7.5%higher than that of the traditional structure.The experimental results are consistent with the simulation results of APSYS,which shows that the inverted triangle structure has a better application prospect.