Heterogeneous Integration of Microscale GaN Light‐Emitting Diodes and Their Electrical, Optical, and Thermal Characteristics on Flexible Substrates

TLDR

The study presents materials and device strategies for creating inorganic, thin‑film microscale LEDs using a simplified release method. High‑performance GaN blue micro‑LEDs were fabricated on patterned and non‑patterned sapphire substrates, released, and transferred onto copper and polyimide flexible substrates, with their thermal properties systematically examined across these substrates. The transferred micro‑LEDs retained electrical and optical performance, enabled polychromatic emission with phosphor coatings, and suggest promising applications in lighting, displays, and biomedicine.

Abstract

Abstract Materials and device strategies to form inorganic, thin‐film, microscale light‐emitting diodes (micro‐LEDs) are presented based on a simplified release method. High performance gallium nitride based blue micro‐LEDs are fabricated on and released from both patterned sapphire substrates (PSSs) and conventional nonpatterned sapphire substrates (CSSs). Micro‐LEDs are transferred onto copper and polyimide based flexible substrates and their electrical and optical performances are maintained. Thermal properties of PSS and CSS based micro‐LEDs are systematically explored on different substrates. Finally, micro‐LEDs combined with phosphor coatings demonstrate capability for polychromatic emission. The techniques presented here provide promising paths to advanced light sources with potential applications in lighting, displays, and biomedicine.