(Invited) High Output Power Deep Ultraviolet Light Emitting Diodes with Hemispherical Lenses Fabricated Using Room Temperature Bonding
We reviewed the structural and optical properties of high output power 255 and 280 nm light emitting diodes (LEDs) bonded with hemispherical lenses made of inorganic materials. [This is described as a full paper (and not a review) Is this your intended meaning?[This is my intended] The optimal LED structure with a lens to improve the output power for deep ultraviolet LEDs was designed using Monte Carlo simulation. The LED chips were bonded to sapphire lenses at room temperature using either atomic diffusion bonding or surface activated bonding. The bonding of the lenses to the LEDs is experimentally shown to improve the light extraction efficiency, and the light output power of the LEDs with lenses was significantly higher than that of conventional structure LEDs. The output power of a 255 nm LED with a lens was 2.8 times larger than that without a lens, with a maximum external quantum efficiency of 4.56% and that of the 280 nm LED with a lens was larger by a factor of 2.3.