Xiamen University, crack deep UV LED application problems

Xiamen University Physics and Mechanical and Electrical Engineering by a research team high alumina component nitride deep UV LED surface covered with a layer of ultra-thin aluminum film to crack the constraints of this light-emitting device to the wider application of the key challenges of the light extraction efficiency open new methods and ideas in the field of health care, environmental protection, military industrial applications for such devices in the future.

So-called deep UV, refers to the wave length at 280 nm UV. This light source in water and air purification, and play a unique role in disease treatment, information technology and other fields. But a long time, limited by the intrinsic characteristics of the high alumina component nitride was present and preparation process, deep ultraviolet light is extracted from the light emitting diode is very low efficiency, which means that little electricity into a portion of the available light, resulting in a "light "drain, has greatly restricted the wider application of deep ultraviolet light-emitting diodes.

Building Physics and Electrical Engineering Professor research group under 64 and 128 atom supercells the geometric task group to look "locked" in the study. After several years of research, a member of the task group associate professor Huang Kai and doctoral high Na borrow an ultra-thin aluminum film to crack this problem: when the research group in a deep ultraviolet light emitting diodes plated on ultra-thin layer of only 5 nanometers aluminum, surprised to find that layer aluminum film not only does not like a traditional mirror device emitted light is reflected back, but cleverly device to the side of the emitted light collected through the aluminum layer, magic is emitted from the front, to achieve improvement of light extraction efficiency.

Huang Kai explained, "This is the very thin aluminum film do because when the nano effect makes it different from the traditional mirror reflecting the light back, but concentrated absorption, light collection and positive emission."

The tests showed that the "coat" of this layer of aluminum on the contribution of the ultraviolet LED light extraction efficiency will vary with wavelength. Generally speaking, the shorter the wavelength of light, the higher the efficiency. Data show that the same is plated on this layer of aluminum film, a wavelength of about 310 nm ultraviolet LED, the light extraction efficiency can be increased by about 20%; wavelength of about 290 nm ultraviolet LED, light extraction efficiency can be increased by about 50%; For a wavelength of about 280 nm deep ultraviolet light-emitting diode, the light extraction efficiency can be increased to 130%.