Flexible arrays of GaN-based Micro-LED fabricated on different substrates by laser lift-off process

Abstract

Fabrication of flexible micro-light-emitting diodes (Micro-LEDs) is becoming an important technology for flexible displays, which plays a significant role in the field of visual communication in the upcoming internet of things era and metaverse. Here, we explore high-quality laser lift-off methods for gallium nitride (GaN)-based Micro-LED arrays using laser lift-off (LLO) technology to separate Micro-LED arrays from sapphire substrates via a KrF excimer laser system (λ = 248 nm). Ultimately, we used viscoelastic stamp transfer technology to successfully transfer Micro-LED arrays to various types of substrates, including tape and copper foil (Cu), thus enabling applications in different scenarios. The results show that the threshold voltage and EL intensity of Micro-LEDs on the tape and Cu substrates increase slightly, and the peak of the electroluminescence (EL) spectrum was basically stable at 458nm. Furthermore, Micro-LEDs on polyethylene terephthalate (PET) can still work normally when the bending radius of PET is 4 cm.