Reserch On Growth Conditions Of Well Layer Material Of GaN Based UV-LED MQWs

Ga N based ultraviolet LED has been widely used in industry and daily life due to its advantages of high brightness, low energy consumption, strong durability,safety and environmental protection. However, the efficiency of Ga N based ultraviolet LED with multiple quantum wells is still very low, which severely limits its development. So, how to improve the luminous efficiency of ultraviolet LED, especially its internal quantum efficiency has become a hot research for domestic and international institutions. The purpose of this paper is to improve the luminous efficiency of ultraviolet LED device by improving the growth quality of the quantum well layer material. In this paper, the basic characteristics of LED device are introduced, and the methods to improve the efficiency of LED are compared, and the growth model of In Ga N is given.Then, the growth temperature and In flow are optimized by the growth model. Through the test and analysis of the experimental samples, the conclusions are drawn.The main results of this paper are as follows:In view of the influence of the growth temperature on the quality of potential well layer material, this paper first carries out a series of experiments on the growth temperature. And the samples are tested for material and device characteristics.The test results show that the dislocation density decreases with the increase of the growth temperature, and the PL intensity increases correspondingly. The test results also show that the In component is not significantly affected by the change of the low temperature when the In flux is low. Through the test of the electrical properties of the final device, it is found that the increase of the growth temperature of the potential well layer has a positive effect on the LED emission efficiency, and the leakage of the device is improved to some extent.Due to the low In flow rate in the experiment, the paper has carried on the improvement of the In flow experiment. Through the test and analysis of the experimental samples, it can be shown that with the increase of In flow, the In component of the quantum wells is gradually increased. The growth quality of material can be improved at first, but when the In flow increases to a certain value, the dislocation density increases with the increase of In flux. At the same time, the large In flux is also found to lead to the decrease of the emission intensity of the quantum wells. The energy band structure analysis shows that the enhance of the doped In flow will increase the stress between the well and the barrier layers, and the quantum confined Stark effect will be more significant. The results of the final test point out that the increase of In flow rate will increase the emission wavelength and improve the luminous efficiency.A third set of experiments are carried out to adjust the growth temperature and In flux,so that the devices with the same light emitting wavelength can be obtained. The analysis of the test results shows that the sample has good material and electrical characteristics when the growth temperature of the potential well layer is 810?, and the In flux is 15%. Finally, the emission power of the device is 43.33 m W at the emission wavelength of 363.82 nm. The luminous efficiency of the device is improved by 22.5%, which indicates that the efficiency of LED is effectively improved by the way of improving the growth quality of the potential well layer material.