Public Release: 


Ludwig-Maximilians-Universität München

The color of the light emitted by an LED can be tuned by altering the size of their semiconductor crystals. Ludwig-Maximilians-Universitaet (LMU) in Munich researchers have now found a clever and economical way of doing just that, which lends itself to industrial-scale production.



The crucial element in the new method is a thin wafer, only a few nanometers thick, which is patterned like a waffle. The depressions serve as tiny reaction vessels, whose shape and volume ultimately determine the final size of the nanocrystals. "Optimal measurements of the size of the crystals were obtained using a fine beam of high-energy X-radiation at the Deutsche Elektronen-Synchrotron (DESY) in Hamburg", says LMU researcher Dr. Bert Nickel, member of the Nanosystems Initiative Munich (NIM), a Cluster of Excellence.

Moreover, the wafers are produced by means of an economical electrochemical process, and can be fashioned directly into LEDs. "Our nanostructure oxide layers also prevent contact between the semiconductor crystals and deleterious environmental factors such as free oxygen and water, which would otherwise limit the working lifetime of the LEDs," as Dr. Martin Kaltenbrunner of the Johannes Kepler University in Linz explains. In the next step, we want to enhance the efficiency of these diodes further, and explore their potential for use in other applications, such as flexible displays.

