Ohio State researching ways to improve LED efficiency

Posted: November 6, 2013

Professor Siddharth Rajan
Research being performed at The Ohio State University is designed to reduce the effects of efficiency droop in certain LEDs and other optoelectric devices. An article on this research is in the current edition of Semiconductor Today.

According to Siddharth Rajan, associate professor in the Department of Electrical and Computer Engineering, the research will employ the use of a newly developed tunnel junction as a means to ameliorate the effects of efficiency droop in nitride semiconductor light-emitting diodes (LEDs) and other optoelectronic devices.

While the peak efficiency point of such devices can be as low as a few milliamps (and with the power rating in the tens of milli-watt range) general illumination requires devices operating at the order of one watt of power. The result is that LED bulbs need a large number of LEDs – around 100 if operating at peak efficiency. Economic constraints lead to trade-offs between production costs and efficiency.

The Ohio State proposal would be to cascade a series of LEDs in a vertically integrated monolithic structure with a number of devices coupled in series and operated at low current injection while a high voltage is applied across the whole assembly.

Read the complete article from AIP Scitation here.