ZnO nanorod LED emits broadband blue-white light

May 1, 2011
Zinc oxide (ZnO) is a semiconductor with a bandgap in the UV, making it potentially useful as an alternative to gallium nitride for blue- and UV-emitting laser diodes and LEDs.

Zinc oxide (ZnO) is a semiconductor with a bandgap in the UV, making it potentially useful as an alternative to gallium nitride for blue- and UV-emitting laser diodes and LEDs. But p-type doping of ZnO is difficult, and means that instead of getting by with the usual single large semiconductor crystal as an emitter source, ZnO-based emitters rely on the use of nanocrystalline structures, resulting in unusual devices such as random lasers. Now, a group at Dongguk University (Seoul, Korea) and the Institute of Microelectronics Technology (Moscow, Russia) working with ZnO nanorod arrays are creating broadband blue-white LEDs that contain on the order of 109 nanodiodes per square centimeter. The nanodiode crystals are grown vertically on a transparent indium-tin-oxide-coated glass substrate; the crystals are then contacted and fixed to a silicon wafer with transparent epoxy.

The devices, which are 2 × 2 cm in size and have a luminance of 30 cd/m2, currently exhibit a low luminous efficiency of 0.2 lm/W but offer many options to improve this figure. The electroluminescence (EL) is broadband, reaching from 350 to beyond 800 nm under a forward bias of 9 V. The researchers are now working to create a high-efficiency pure-UV version of the LED.

Contact Gennady Panin at [email protected].

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

Working with Optical Density

Feb. 26, 2025
Optical Density, or OD, is a convenient tool used to describe the transmission of light through a highly blocking optical filter.

Custom-Engineered Optical Solutions for Your Application

Feb. 26, 2025
Explore the newest and most widely used applications of Semrock optical filters.

Linear Stages & Rotary Stages for High Precision Automation & Motion Control

Feb. 13, 2025
Motorized Linear Translation Stages & Rotary Precision Positioning Stages for High Performance Automation & Motion Control | PI USA

Motion Controllers for Precision Positioning and Automation

Feb. 13, 2025
PI manufactures a range of precision motion controllers and drivers for positioning systems, including stepper motors, brushless motors, and servo motors.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!