Low-Cost Zinc Oxide for High-Power-Output, GaN-Based LEDs (UC Case 2010-150)

Brief Description

This method produces an LED structure using ZnO nanorod arrays on surfaces other than the (0001) p-GaN surface and also on multiple surfaces of the LED. 

Background

To improve the light extraction efficiency of LEDs, transparent conductive oxides (TCOs) with high refractive indices — such as indium-tin-oxide (ITO), zinc oxide (ZnO), aluminum-doped-zinc-oxide (AZO) — are widely used. Films of these materials increase the probability of light escaping the LED through the TCO, thus increasing overall light output. ITO, however, is cost prohibitive, making zinc oxide films a better choice for commercial scalability. 

Description

This method produces an LED structure using ZnO nanorod arrays on surfaces other than the (0001) p-GaN surface and also on multiple surfaces of the LED. The ZnO nanorod arrays can be synthesized using low-cost solution processing methods and produced on various LED surfaces such as GaN-faced C-plane surfaces, non-polar and semi-polar surfaces, and also non-GaN surfaces such as substrates and transparent current-spreading layers. It enhances light output from both lateral and vertical-type LEDs.

Advantages

• Increased light output
• Low-cost fabrication

Applications

• LEDs
• Solar cells
• GaN-based devices

Patent Status