Tunnel spin injection into graphene using Al2O3 barrier grown by atomic layer deposition on functionalized graphene surface

We demonstrate electrical tunnel spin injection from a ferromagnet to graphene through a high-quality Al2O3 grown by atomic layer deposition (ALD). The graphene surface is functionalized with a self-assembled monolayer of 3,4,9,10-perylene tetracarboxylic acid (PTCA) to promote adhesion and growth of Al2O3 with a smooth surface. Using this composite tunnel barrier of ALD-Al2O3 and PTCA, a spin injection signal of 30 ohm has been observed from non-local magnetoresistance measurements at 45 K, revealing potentially high performance of ALD-Al2O3/PTCA tunnel barrier for spin injection into graphene.