Electrically Driven Sub‐Micrometer Light‐Emitting Diode Arrays Using Maskless and Etching‐Free Pixelation

Abstract

For decades, group‐III‐nitride‐based light‐emitting diodes (LEDs) have been regarded as a light emitting source for future displays by virtue of their novel properties such as high efficiency, brightness, and stability. Nevertheless, realization of high pixel density displays is still challenging due to limitations of pixelation methods. Here, a maskless and etching‐free micro‐LED (µLED) pixelation method is developed via tailored He focused ion beam (FIB) irradiation technique, and electrically driven sub‐micrometer‐scale µLED pixel arrays are demonstrated. It is confirmed that optical quenching and electrical isolation effects are simultaneously induced at a certain ion dose (≈1014 ions cm−2) without surface damage. Furthermore, highly efficient µLED pixel arrays at sub‐micrometer scale (square pixel, 0.5 µm side length) are fabricated. Their pixelation and brightness are verified by various optical measurements such as cathodo‐, photo‐, and electroluminescence. It is expected that the FIB‐induced optical quenching and electrical isolation method can pioneer a new defect engineering technology not only for µLED fabrication, but also for sub‐micrometer‐scale optoelectronic devices.

Directly Printable Flexible Optoelectronics through Surface Atomic Modification of Liquid Metals at Room Temperature

“…Figure 7b shows the fluorescent pixels produced by the direct printing and surface modification of eGaIn-based patterns and the application of fluorescent pixels in flexible optoelectronics such as flexible displays and flexible lights (Figure S14: Supporting Information). 54 Figure 7c illustrates the direct fabrication of liquid metal pixels on the PI flexible substrate by printing, which were transformed into the flexible fluorescent pixels (Figures 7d and S15: Supporting Information) through modification with ammonia aqueous solutions. Importantly, the feasibility of this strategy in flexible optoelectronic applications has been demonstrated.…”

The micro-LED roadmap: status quo and prospects

“…Therefore, researchers have dedicated significant efforts to achieving high EQEs of over 30% for micro-LEDs, particularly at lower current densities to minimize heat generation and provide sufficient brightness for XR displays. Several promising approaches have been implemented recently, including multiple passivation layers to reduce non-radiative recombination [165], damage-free pixelation through direct epitaxial growth [98], neutral beam etching [166], focused ion-beam irradiation [167]. These techniques have successfully fabricated sub-5 µm micro-LEDs with EQEs exceeding 10%, although full-color displays using these methods are not yet available.…”