Meaglow Ltd of Thunder Bay, Ontario, Canada – a privately held firm that produces a range of epitaxy equipment and MBE and MOCVD accessories, as well as providing specialized thin films to research institutes and industry - says that its low-temperature Migration Enhanced Afterglow film growth technique has been used to produce a thick indium gallium nitride (InGaN) layer with strong yellow emission. The firm reckons that this result bodes well to increase the efficiency and to lower the production costs of green LEDs and laser diodes.
The company is currently seeking collaboration opportunities to enhance the material properties required by industry for lighting, display, medical, and military applications, among other uses.
"It's the brightest p-n junction I've ever seen in my life, and its right in the green gap," says Meaglow's chief scientist professor K. Scott Butcher. "The green gap (540-610nm) is a major unsolved obstacle towards the development of high-efficiency solid-state lighting applications," he adds.
LEDs produced in the green region, between red and blue, have rapidly declining efficiency. Green and yellow in the middle of the color spectrum, known as the 'green gap', is a section of the light spectrum where devices made from either nitride or phosphide are inefficient and difficult to fabricate. Meaglow's reactor overcomes these difficulties by utilizing its patent pending hollow cathode and low-temperature growth process, which is capable of growing the volatile compound of indium required to make green and yellow diodes, says Butcher.
Having a nitride device that emits strongly in the yellow is a big step forward for low-temperature InGaN growth and demonstrates the quality of InGaN produced by the proprietary Meaglow technique, says the firm. Results for this test device were presented to the nitride semiconductor research community in May at the 9th International Symposium on Semiconductor Light Emitting Devices (ISSLED2012) at TU Berlin, Germany.
