The Effect On Light Efficiency By Adjusting The Structure Of GaN-based Long-wave UV-LED Multi-quantum Wells

With the development of recent years, Ga N-based UV-LED becomes the new research hotspot and market focus since Blue LED. Ga N-based UV-LED has the advantages of small size, long life, environmental protection and durability, etc. It has broad application prospects in the new generation of ultraviolet light source. Long-wave of 365 nm is a typical wavelength of the traditional ultraviolet light source which is widely used in curing, exposure, security and other fields. However, the luminous efficiency of this long-wave band Ga N-based UV-LED is still very low for the present, its luminous performance can not meet the market demand, so it can not completely replace the traditional long-wave ultraviolet light source. Therefore, a further study of 365 nm long-wave UV-LED and developing the devices that have better photoelectric properties have great important significance and great influence on the future of UV-LED to replace the traditional ultraviolet light source and widely used in various fields of market.This thesis mainly concerned the effect on light efficiency by adjusting the structure of Ga N-based UV-LED multi-quantum wells.We hope the luminous performance of 365 nm UV-LED can be improved by the adjustment. Firstly, this thesis introduces the general situation and development of both LED and UV-LED. Then, it also introduces some properties of Ga N-based materials in detail. After that, it makes an introduction of the growth material technology-MOCVD in detail and fully describes the characterization methods used in experiments which include XRD, PL, EL, AFM and SEM. Finally, we design experiments to achieve the purpose of improving the luminous efficiency by adjusting the Al content in barrier layer and the well width of the quantum well. The two parts of the experiment results are as follows:1. Two batch experiments are carried out to adjust the width of the In Ga N/Al Ga N quantum well. Under the condition of 365 nm wavelength, the first batch experiments determine that the optimal range of luminous properties is 2 times to 5 times the well width. The second batch experiments determine the optimum width of 3 times which makes both the luminous properties and the luminous efficiency of the epitaxial wafer be the best. Finally, we can get the result of improving the luminous efficiency of 365 nm Ga N-based long-wave UV-LED by adjusting the quantum well width.2. Two batch experiments are carried out to adjust the Al content in barrier layer of the In Ga N/Al Ga N quantum well. Under the condition of 365 nm wavelength, the first batch experiments determine that when the Al content in barrier layer is increased from 5 percent, both the luminous performance and the luminous efficiency become worse. The second batch experiments determine that when the Al content in barrier layer is decreased from 5 percent, the light intensity is slightly lower. So 5 percent of the Al content in barrier layer is the best. Finally, we can get the result of improving the luminous efficiency of 365 nm Ga N-based long-wave UV-LED by adjusting the Al content in barrier layer.Through the experiment results of tow batches of two parts, we basically achieve that we can improve the luminous efficiency of 365 nm Ga N-based long-wave UV-LED by adjusting the structure of the quantum well, which also reached the purpose and significance of this thesis.