Heterogeneous integration of single-crystalline rutile nanomembranes with steep phase transition on silicon substrates
Dong Kyu Lee, Yunkyu Park, Hyeji Sim, Jinheon Park, Younghak Kim, Gi‐Yeop Kim, Chang‐Beom Eom, Si‐Young Choi, Junwoo Son
Abstract
Abstract Unrestricted integration of single-crystal oxide films on arbitrary substrates has been of great interest to exploit emerging phenomena from transition metal oxides for practical applications. Here, we demonstrate the release and transfer of a freestanding single-crystalline rutile oxide nanomembranes to serve as an epitaxial template for heterogeneous integration of correlated oxides on dissimilar substrates. By selective oxidation and dissolution of sacrificial VO 2 buffer layers from TiO 2 /VO 2 /TiO 2 by H 2 O 2 , millimeter-size TiO 2 single-crystalline layers are integrated on silicon without any deterioration. After subsequent VO 2 epitaxial growth on the transferred TiO 2 nanomembranes, we create artificial single-crystalline oxide/Si heterostructures with excellent sharpness of metal-insulator transition ( $$\triangle \rho /\rho$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>△</mml:mo> <mml:mi>ρ</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ρ</mml:mi> </mml:math> > 10 3 ) even in ultrathin (<10 nm) VO 2 films that are not achievable via direct growth on Si. This discovery offers a synthetic strategy to release the new single-crystalline oxide nanomembranes and an integration scheme to exploit emergent functionality from epitaxial oxide heterostructures in mature silicon devices.