Xiamen University crack deep ultraviolet light emitting diode applications

A research team of physical and mechanical and Electrical Engineering College of Xiamen University through the nitride deep ultraviolet light-emitting diode in high Al group (LED) is covered with a layer of thin aluminum film surface, and a light emitting device to break the constraints of the application of "light extraction efficiency" problem, open the new methods and ideas for the future of such devices industrialization used in medical, environmental, military and other fields.

Xiamen University 12, said that the results of this study, has been published in "nature" Publishing Group's online publication covering open "all fields of natural sciences scientific reports on".

The so-called deep ultraviolet, refers to the wave length of 280 nm uv. This light source can play a unique role in water and air purification, disease treatment, information technology and other fields. But for a long time, due to the high aluminum nitride component properties and preparation process, the efficiency of the light emitting diode from deep UV is very low, which means that the available light electricity into small parts caused by the "light" of the loss, greatly restricts the wider application of deep ultraviolet light emitting diode.

The group of Professor Kang Junyong research group under the topic of physical and mechanical and Electrical Engineering College of Xiamen University will look to the "lock" study. After several years of research, associate professor Huang Kai and members of the research team of doctoral Gao Na borrow a ultrathin aluminum film solve this problem: when the research group in a deep ultraviolet light-emitting diode coated ultrathin aluminum film layer of only 5 nm, was surprised to find that this layer of aluminum film not only did not like the traditional the mirror will emit light device more reflected, but cleverly collected device to side the light emitted through the aluminum film, the magic shot from the front, the light extraction efficiency.

This is because when the aluminum film is very thin, the nano effect makes it different from the traditional mirror to reflect the light back, but the concentration of absorption, to achieve the collection of light and positive emission. "

The results show that the "contribution" to the light extraction efficiency of the ultraviolet light emitting diode will be different with the wavelength. Generally speaking, the shorter the wavelength, the higher the efficiency. Data show that the same is plated on this layer of aluminum film, light emitting diode wavelength of about 310 nm ultraviolet light, the light extraction efficiency can be increased by about 20%; the light emitting diode wavelength of about 290 nm ultraviolet light, the light extraction efficiency can be increased by about 50%; and for the wavelength of about 280 nm deep ultraviolet light emitting diode two, light extraction efficiency it can be increased by 130%.

This result makes the members of the research group greatly encouraged. At present, they are still in the process of improvement, and strive to further improve the efficiency of deep ultraviolet light emitting diodes.