GaN LED UV Pumped Multi-Color & White Light Phosphors Using Innovative Immersion Techniques for Display Applications

The use of UV LEDs for creating visible light by exciting commercially available phosphors will be explored. LEDs based on the (InAlGa)N materials system, now currently used to produce high brightness blue and green LEDs, will be developed to emit efficiently at UV wavelengths corresponding to the excitation bands of various phosphors. By using UV emission from LEDs to excite standard phosphors to emit at differing visible wavelengths, a new approach for fabricating innovative, efficient white light sources as well as multicolor displays can be explored. In this project, the growth of (InAlGa)N will be optimized to produce device structures which will emit efficiently in the UV to violet region between 380 and 420 nm. Complete LED structures will be grown and LEDs will be fabricated so the UV emission characteristics such as wavelength and efficiency can be measured. Various means of coupling the output of UV LEDs to thin films containing phosphors, including novel methods such as the use of resonant cavities and waveguides, will be used to explore the feasibility of developing efficient white light sources and multicolor displays which use a single wavelength LED active element. This is particulary attractive since current LED display technologies require combining active elements fabricated from a variety of different and incompatible material systems. The availability of efficient, high brightness UV LEDs combined with high efficiency phosphors properly coupled to the LED emission would lead to a whole new class of bright, efficient and highly reliable light sources and color displays with widespread applications in both military and consumer products.