Centimeter-Transferable III-Nitride Membrane Enabled by Interfacial Adhesion Control for a Flexible Photosensitive...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Flexible III-nitride optoelectronics are vital for UV applications but face challenges in epilayer separation due to strong substrate adhesion.
• Van der Waals epitaxy (vdWE) with graphene offers a route to weaken adhesion, but controlling it for intact membrane transfer remains difficult.

Purpose of the Study:

• To demonstrate controlled interfacial adhesion in III-nitride van der Waals epitaxy (vdWE) for creating transferable membranes.
• To investigate the effect of graded high-temperature nitridation of graphene on vdWE interfacial properties and III-nitride growth.

Main Methods:

• Utilized graded high-temperature nitridation of a graphene insertion layer to create controlled defects and nitrogen doping.
• Achieved different epitaxial modes (pure-vdWE, quasi-vdWE, mixed) by tuning interfacial adhesion.
• Employed UV resin-assisted bonding for transferring the III-nitride membrane onto a flexible substrate.

Main Results:

• Quasi-vdWE, facilitated by minor graphene defects and nitrogen doping, lowered AlN nucleation energy.
• Proper interfacial adhesion ensured the integrity of the III-nitride membrane during growth and enabled centimeter-scale separation.
• Fabricated flexible photodetectors with high yield (90%) and good durability (retaining ~60% performance after 250 bending cycles).

Conclusions:

• A promising strategy for controlling vdWE interfacial adhesion in III-nitride epitaxy was developed.
• Separable and transferable III-nitride membranes are established, paving the way for advanced UV foldable and wearable devices.