Nitride-Based Type-II InGaN-(In)GaNAs 'W' Quantum Well Gain Media for Solid State Lighting Applications

Light Emitting Diodes (LEDs) for Solid State Lightings
● Solid State Lightings to replace general illumination light sources such as fluorescent and incandescent
lamps (by 2025, based on estimation by US Department of Energy, February 2006).
● Solid State Display Applications (ie. Traffic Lights, Signage, etc)
● Efficient Liquid Crystal Display (LCD) Backlight for LCD Televisions, LCD monitors on laptop
computers, and various custom sized LCD displays.
● Diode Lasers for DVD Applications.
● Emerging Technology of High-Definition and True-Color Television Using LEDs-based Pixels (ie.
Sony Qualia).
● Entertainment Lighting effects and luminaries for theatres, studios, nightclubs, entertainments,
restaurants and other high-visibility venues. Ability to provide “tunable” white and capable of digitally
producing any color under the rainbow.
● Durable low voltage Landscape Lighting, for city beautification, park or residential project.
● Portable Lighting using this technology is sturdy as there are no fragile components to break compared
to filament bulb. The need to replace a bulb is eliminated. Portable applications using this technology can
benefit from improved battery life and light output.

Diode Lasers for Medical Applications
● For Eye Surgery and Glaucoma Therapy (Trabeculoplasty Procedure) using diode lasers emitting at
532-nm wavelength regime (green)
● Photodynamic Therapy for Non-Invasive Cancer Treatment.

Solid-State Automotive Displays and Lightings
● High brightness, low power LEDs for interior and exterior automotive lighting with small footprints that
offer improvement in safety, durability, and design.

● Depositing the active regions on GaN or sapphire substrates using a low-cost commercial processing step of MOCVD (metal organic chemical vapor deposition).
● Blue laser diode and LEDs based on conventional technology of InGaN QW suffers from poor performance (ie. high
threshold current and low efficiency). The invention would enable the realization of high-performance and lowthreshold-
current blue laser diode, for DVD applications. The invention would also allow the realization of high-efficiency
blue LEDs on III-Nitride template, which is crucial in realizing a low-cost and high-efficiency solid state
lighting.
● Up to today, green laser diode based on conventional technology of InGaN QW has not been realized yet, and this is
due to the poor optical gain of the conventional active region. The poor electron-hole wavefunction overlap in the
conventional approach also leads to very low radiative efficiency of the green LEDs. The invention would allow the
realization of high-efficiency green LEDs on III-Nitride template (attributing to the significantly-larger electron-hole
wavefunction overlap), which is crucial in realizing a low-cost and high-efficiency solid state lighting. The invention
would also pave the way to the realization of first high-performance and low-threshold-current green laser diode,
which would be a technology of great importance in the medical applications.
● Red LEDs based on conventional InGaN QW technology has very poor efficiency, and no diode lasers emitting in
the red regime have been realized by using the conventional technology. The invention can be extended from green
regime to longer wavelength regime (up to yellow or red), thus resulting in large optical gain active region based on
this technology. This invention would allow the realization of high-efficiency yellow or red LEDs on III-Nitride template (attributing to the significantly-larger electron-hole wavefunction overlap), which is a key technology for
monolithic integration of blue-green-red LEDs on a single chip for low-cost and high-efficiency solid state lighting.