Inorganic light-emitting diodes (LEDs) are bright, stable and efficient, but usually emit only one colour. Gyu-Chul Yi at Seoul National University and his team have created LEDs that can be tuned continuously from red to blue (pictured) for potential use in the display screens of mobile devices.
Their LED consists of nanorods of the semiconductor gallium nitride, each coated with layers of indium gallium nitride. These layers form 'quantum wells' that restrict the movement of electrons, altering the electrons' energy levels and, ultimately, determining the wavelength of the LED's emitted light. The thickness of the layers varies naturally as they are deposited on the rods' multi-faceted tips. By altering an applied voltage, the researchers force electric current to travel through layers of different thickness, thus changing the colour of light that the LED emits.
Rights and permissions
About this article
Cite this article
Rainbow from a single LED. Nature 474, 254 (2011). https://doi.org/10.1038/474254c
Published:
Issue Date:
DOI: https://doi.org/10.1038/474254c
