Transfer of a Well-Aligned TiO2 Nanorod Array onto GaN-Based LEDs for Light Extraction Enhancement

Abstract

We report on the application of a transferable titaniumdioxidenanorod (TiO2 NR) array as a light extraction booster forGaN-based light-emitting diodes (LEDs). A chemical lift-off processwas used to create a self-separating TiO2 NRs array, whichwas achieved during growth of TiO2 NRs on a nickel (Ni)-metal-coatedSi substrate. The array was transferred onto the topmost layer ofthe LED chip. The TiO2 NR array/LEDs show the 66% enhancementof light output power (LOP) intensity compared with the referenceLEDs at a fixed injection current of 100 mA. The transferable TiO2 NR array formed on the LEDs is a very effective structureto increase light extraction by reduction of backward reflectionsof photons emitted from LEDs. Our suggested simple and practical methodsuggested by our team to facilitate self-separation of the transferableTiO(2) NRs array can be applied on various substrates foroptoelectronic devices without additional damage or degradation ofdevice performance.