To prove that the newly grown materials were as fit as the bulk substrate to design electronic devices, the researchers grew AlGaInP–GaInP double heterojunction light-emitting diodes (LEDs) on a graphene-overlaid GaAs substrate. The LEDs not only exhibited I–V curves and turn-on voltages (1.3V) comparable to those of LEDs directly grown on a bare GaAs substrate, their electroluminescence spectra also exhibited nearly identical performance.
The LEDs were then exfoliated from the GaAs substrate (leveraging the graphene layer as a non-stick interface from which the active layers could be peeled-off) and transferred to a Si substrate without noticeable performance degradation. The layers being peeled-off are only a few micrometres thick and the graphene-coated wafer remains untouched, ready for re-use without ever being sacrificed in the end-device. That means enormous cost savings, especially so when having to rely on non-silicon substrates.
"Since the epilayers grown by remote homoepitaxy can be released from the graphene surface, this 2D material-based layer transfer (2DLT) technique offers the potential to grow, transfer and stack any electronic and photonic materials on 2D materials without the lattice matching limitation. This will open a pathway towards defect-free hetero-integration of dissimilar materials while saving the cost of expensive and exotic substrates" concludes the paper.
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