CVD Bilayer Graphene Spin Valves with 26 μm Spin Diffusion Length at Room Temperature
Timo Bißwanger, Zachary Winter, Anne Schmidt, Frank Volmer, Kenji Watanabe, Takashi Taniguchi, Christoph Stampfer, Bernd Beschoten
Abstract
We present inverted spin-valve devices fabricated from chemical vapor deposition (CVD)-grown bilayer graphene (BLG) that show more than a doubling in device performance at room temperature compared to state-of-the-art bilayer graphene spin valves. This is made possible by a polydimethylsiloxane droplet-assisted full-dry transfer technique that compensates for previous process drawbacks in device fabrication. Gate dependent Hanle measurements reveal spin lifetimes of up to 5.8 ns and a spin diffusion length of up to 26 μm at room temperature combined with a charge carrier mobility of about 24 000 cm 2 (V s) −1 for the best device. Our results demonstrate that CVD-grown BLG shows equally good room temperature spin transport properties as both CVD-grown single-layer graphene and even exfoliated single-layer graphene.