SBIR Phase II: Microdisplays Based on III-Nitride Wide Band Gap Semiconductors

The goal of this SBIR Phase II project is to bring the demonstrated Gallium Nitride (GaN) microdisplay technology to industrial maturity and to final commercialization levels. The project's goal will be accomplished by further optimizing the microdisplay device structural design and fabrication process based on the demonstrative results obtained in Phase I. Based on high-efficiency semiconductor micro-light-emitting diode (microLED) array technology, the GaN microdisplay is the first of its kind based on semiconductor LEDs. Specifically, by the hybrid integration of GaN microLED arrays with Si CMOS driver circuits through flip-chip bonding, active matrix addressable GaN microdisplays will have a compact size and will be able to support more information content and movie display due to their high pixel filling factor, uniformity, luminance, and power efficiency. The unique intrinsic properties of GaN microLEDs - high brightness (> 10 microwatt optical output power for microLEDs of 18 micrometer in diameter), wide viewing angle (~ 160 degrees), fast response time (< 1 ns), and high thermal and vibrational resistance, make GaN microdisplays a perfect solution for environmentally demanding applications such as head-up displays (HUD) in modern vehicles and aircrafts, head-mounted displays (HMD) for firefighters and other rescue operatives, and hand-held mini-projectors for field applications. Microdisplays have a small size (typically less than 1 inch diagonal) with a resolution from low end to above XVGA format. They are magnified by optics to form enlarged virtual or projected images for viewing by a user. Microdisplays can be used in a variety of devices such as head-mounted displays, video headsets, camcorder viewfinders, projection TV, head-up displays, etc. and have many commercial applications. GaN microdisplay, with its superior performance over other microdisplay technologies, is especially suitable for environmentally demanding applications that require high brightness, high reliability, and wide operating temperature range. With a slight modification of the material composition, GaN microLED arrays developed here can vary the emitted wavelength from the green to the ultraviolet range, which is very suitable for fluorescence analysis used in new type chemical-biology agent detector array or DNA/protein microchips. The GaN microLED array also has the potential for applications such as optical links and parallel computing. Other applications also include spatially resolved optical studies of biological, medical, and health care systems. The research will also enrich the general knowledge of wide bandgap semiconductor micro- and nano-photonics.