GaN Spin Light‐Emitting Diodes Fabricated by Wafer Bonding Technique: Structural, Spin, and Optoelectronic Properties

GaN‐based spin light‐emitting diodes (spin‐LEDs) are attractive for realizing room‐temperature spin‐controlled light emission in efficient, color‐tunable devices. In this work, we demonstrate spin injection in a GaN spin‐LED fabricated on a Si substrate using wafer‐bonding technology. An inverted n‐i‐p LED structure with n ‐type GaN on top facilitates the injection of spin‐polarized electrons from a ferromagnetic Au/Co/MgO spin‐injector layer grown by molecular beam epitaxy. At room temperature, an electroluminescence circular polarization of approximately 8% is measured under an applied 1 T out‐of‐plane magnetic field in a surface‐emitting geometry. After considering contributions from the Zeeman effect and magnetic circular dichroism, about 6% circular polarization is attributed to the pure spin injection into GaN. This work is focused on the detailed structural and interface characterization of the spin‐LED and allows to understand its spin and optoelectronic properties. These results highlight the potential of GaN‐based spin–optoelectronic devices compatible with Si platforms.