Ultraviolet and Visible Elastic III-N Microwire-Based Light-Emitting Diodes

Nanoscale ultraviolet (UV) and visible light sources are promising for applications in wearable optoelectronic, medical treatment devices and LED applications. Mercury lamps previously employed as UV sources need to be replaced by alternative environmentally friendly sources such as III-nitride-based light emitting diodes (LEDs). In this work, the first flexible UV-A and visible light emitting diodes based on AlGaN/GaN and InGaN/GaN core-shell microwires are demonstrated. The developed devices contain a composite microwire/polydimethylsiloxane membrane with flexible transparent electrodes. It is shown that single-walled carbon nanotube electrodes are preferable and provide a stable electrical contact to the membrane with a high transparency in the and visible spectral ranges. The flexible UV-A and stretchable UV-B membranes demonstrate electroluminescence around 345 and 320 nm. Applying the SWCNT-based electrodes with specific meander-shape current paths provides the stretchability and optical stability of the LED structures. The obtained results pave the way for flexible and elastic inorganic light-emitting diodes to be employed in sensing, detection of fluorescent labels or light therapy.