Sputter-deposited α-MoO3 interlayers for van der Waals epitaxy and film transfer

Abstract Integration of functional thin films onto flexible substrates is driven by the need to improve the performance and durability of flexible electronic devices. We present a van der Waals epitaxy technology that accomplishes the transfer of oxide or metal thin films via exfoliation or dissolution of sacrificial α-MoO 3 layers produced by sputtering. The α-MoO 3 thin films, consisting of weakly bonded two-dimensional layers, grew epitaxially on SrTiO 3 (001) substrates, exhibiting mosaic domains rotated by 90°. Metallic Au films grown on the α-MoO 3 were transferred by mechanical exfoliation or by dissolving the α-MoO 3 in water at 45°C. Spinel-structured CoFe 2 O 4 thin films grown on α-MoO 3 layers were easily transferred to flexible substrates via mechanical exfoliation, and the magnetic anisotropy of the transferred CoFe 2 O 4 films was modulated by bending.