Design And Application Of Wide-spectrum AlGaN-based UV-LED

In the 21 st century,the rise of GaN-based light emitting diodes(LEDs)has undoubtedly changed people's lives.Compared with traditional light sources,LEDs have a smaller volume,longer service life,and higher luminous efficiency,and as a cold light source,it is also very environmentally friendly.Based on the above advantages,LED has developed rapidly and has a very bright prospect.In the field of ultraviolet(Ultraviolet,UV),compared with traditional mercury lamps,solid-state UV-LEDs have the advantages of small size,energy saving and environmental protection,but there are still many challenges in the development of UV-LEDs,such as low luminous efficiency and serious performance degradation.In addition,traditional white LEDs can be realized by combining phosphors and blue LEDs,but if a continuous deep ultraviolet LED light source is to be realized,there is currently no corresponding phosphors that can be combined with UV-LEDs to achieve broad spectrum light emission in the ultraviolet band.Therefore,the research of single-chip wide-spectrum deep-ultraviolet LED has important research significance and practical value.This thesis focuses on the design and research of AlGaN-based deep ultraviolet wide-spectrum LEDs.The main research contents and innovations are as follows:(1)A new design idea for UV-LED devices is proposed,that is,the active area is composed of asymmetric AlGaN,and then based on the band arrangement and carrier distribution and transport,the quantum well is studied by Silvaco simulation software.The influence of structural parameters,quantum well logarithm,quantum well layout,and Al composition selection on the performance of UV-LED devices,further analyze the IV characteristic curve and power density spectrum curve of the designed UV-LED device,and finally optimize an ultraviolet AlGaN-based LED with a larger half-height width is obtained.The designed device has a turn-on voltage of 4.2 V.Under the bias of a 6V forward voltage,the half-height width of the emission spectrum is 17 nm,which is about twice that of traditional UV-LEDs.(2)The 3×3 array UV-LED continuum light source with the luminous wavelength range of 265-400 was prepared by using UV-LEDs with different emission wavelengths,and based on the UV-LED ultraviolet light source,an ultraviolet photoelectric miniature that can be used for water quality COD monitoring was developed.The sensor,the sensor power consumption is less than 3W,the COD monitoring sensitivity is higher than 0.1mg/L,and the measurement period is less than3 minutes,which is suitable for rapid warning of outdoor water COD and other parameters.When the calibrated sensor is used for actual water quality monitoring,the COD test error is less than 5%,the test sensitivity is higher than the standard chemical method,and it is more advantageous for low-concentration COD water monitoring.