Stretchable Transparent Light-Emitting Diodes Based on InGaN/GaN Quantum Well Microwires and Carbon Nanotube Films

Abstract

We propose and demonstrate both flexible and stretchable blue light-emitting diodes based on core/shell InGaN/GaN quantum well microwires embedded in polydimethylsiloxane membranes with strain-insensitive transparent electrodes involving single-walled carbon nanotubes. InGaN/GaN core-shell microwires were grown by metal-organic vapor phase epitaxy, encapsulated into a polydimethylsiloxane film, and then released from the growth substrate. The fabricated free-standing membrane of light-emitting diodes with contacts of single-walled carbon nanotube films can stand up to 20% stretching while maintaining efficient operation. Membrane-based LEDs show less than 15% degradation of electroluminescence intensity after 20 cycles of stretching thus opening an avenue for highly deformable inorganic devices.

Red GaPAs/GaP Nanowire-Based Flexible Light-Emitting Diodes

“…One possible solution to this problem can be a pre-deposition of a thin metallic layer to the n-GaP emitters, effectively reducing potential barrier to n-GaP material: a similar method was used for p-GaN shell of InGaN/GaN blue and green NW covered with 5/5 nm Ni/Au [47,48]. After metallization, the NWs can be contacted with SWCNT or other conductive materials without forming a Schottky barrier [24,26]. The search for a proper thin metallic layer composition for ohmic contact to n-GaP will be the subject of our future studies.…”

“…Therefore, an alternative approach for III-V mi-croLEDs was introduced: nanowire (NW) array devices [23,24]. Benefiting from the high substrate-independency of the NW geometry, flexible [25] and stretchable [26] microLED devices were demonstrated. While for thin film microLEDs the practical application of large area devices is compromised by the necessity of complex post-growth structuring, polydimethylsiloxane (PDMS)/NW membranes of several square inches area were fabricated using a very inexpensive and simple processing [27].…”

“…Here, to the best of our knowledge for the first time we fabricate flexible red GaPAs/GaP NW/PDMS membrane LEDs. The flexible LED was first designed on the basis of numerical simulations and fabricated following previously reported methods [26,27] which were adapted to the challenging geometry of self-catalyzed NWs grown on Si substrates. For comparison, we also studied GaPAs/GaP NWs-based LEDs before array release from the growth Si substrate.…”

Ultra-Flexible Organic Solar Cell Based on Indium-Zinc-Tin Oxide Transparent Electrode for Power Source of Wearable Devices

“…In addition, due to the brittle properties of ITO, cracks or fractures occur with only 2-3% deformation [22,23]. Therefore, the use of organic material-based transparent electrodes with excellent mechanical stability-such as poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS), metal nanowires or meshes, carbon nanotubes and graphene-is increasing [24][25][26][27]. However, due to their low conductivity, poor surface roughness, and complicated manufacturing process compared to ITO, further research on alternative materials to replace ITO is required.…”

Metal-Assisted Chemical Etching for Anisotropic Deep Trenching of GaN Array

“…Significant advantages in photoelectric devices have been shown in GaN due to its higher mobility and higher breakdown voltage [14][15][16]. Currently, GaN micro-/nano-structures are mainly prepared through bottom-up growth and top-down dry etching [17,18]. The epitaxial growth system is complex, and dry etching damages the material.…”