Acousto-fluidic assembly of III-nitride micro-light-emitting diodes with magnetic alignment

A fluidic assembly of III-nitride micro-light-emitting diodes (μLEDs) is demonstrated by applying external forces. This work introduces a solution-based mass transfer approach for inorganic semiconductor devices with the advantages in being material- and dimensional-agnostic. This method offers precise control in device alignment and orientation. The alignment of μLEDs in solution is controlled by acoustic focusing and the induced pressure forces, and the device orientation is modulated using magnetic field. The detailed mechanisms of the use of acoustic focusing and magnetic field are discussed. This fluidic assembly technique allows high throughput rate and roll-to-roll manufacturing, which is critical to the mass transfer of μLEDs for display and functional fabric applications.