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Performance analysis of GaN-based micro light-emitting diodes by laser lift-off process
摘要： In this study, a monochromatic GaN-based micro-light-emitting-diode (μLED) array was fabricated using flip-chip technology. The laser lift-off (LLO) process was employed to decrease the light divergence caused by the differing refractive indexes of sapphire (n = 1.77) and GaN (n = 2.4). The LLO-μLEDs considerably improve light collimation, compared with conventional flip-chip μLEDs containing a sapphire substrate. We highlight, in particular, the importance of the optical characteristics before and after LLO. Collimation of light was discovered to be 12% higher after removal of the sapphire substrate. The results are of high importance for understanding the optical properties of μLED arrays after LLO.
关键词： Light-emitting diodes,Micro-LEDs,Laser lift-off,GaN
更新于2025-09-19 17:13:59
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Femtosecond Laser Lift‐Off with Sub‐Band Gap Excitation for Production of Free‐Standing GaN LED Chips
摘要： A novel method for lifting-off GaN-based LED structures from sapphire substrates is demonstrated. In this approach, ultrashort (350 fs) green pulses are scanned across the sample backside to lift-off the LED, utilizing two-photon absorption at the GaN/sapphire interface. The corresponding fluence regime is carefully investigated. Stable emission properties after laser lift-off are proven by cathodoluminescense measurements.
关键词： GaN,light-emitting diode,femtosecond laser,non-linear optics,laser lift-off
更新于2025-09-11 14:15:04
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Sacrificial layer for laser lift-off process for flexible-display production
摘要： In this study, we developed a new sacrificial layer (SL) for laser transfer process. Metallic substrate i.e. invar foil was temporarily docked to a glass substrate using glass powder. To ensure successful delamination, the SL was pre-deposited between metal foil and glass substrate. For the first time, the SLs were amorphous gallium nitride and non-stoichiometric gallium oxide which were implemented for laser lift off (LLO) processes of metal foil. Bonding of metal foil to glass sheet was performed using heat treatment while debonding was achieved by LLO method. The laser wavelength was 355 nm which was the best fit for full absorption from SL layers. Transmission electron microscopy, element mapping, and energy dispersive X-ray spectroscopy analyses were performed for investigating elements’ migration and bonding-debonding mechanism.
关键词： Gallium oxide,Flexible displays,Gallium nitride,Laser lift-off,Sacrificial layer
更新于2025-09-11 14:15:04