Growth and Transfer of Large‐Area Bi 2 Te 3 Thin Films Using Silicon‐On‐Insulator Technology

Semiconductor nanomembranes offer a scalable platform for integrating layered topological insulators onto arbitrary host substrates. The integration of topological insulator and nanomembrane technologies, such as silicon‐on‐insulator (SOI), remains underexplored, despite the importance of these materials for building flexible quantum devices. This work reports the growth, fabrication, and structural characterization of freestanding Bi 2 Te 3 /Si(111) heterostructure membranes. 50 nm‐thick Bi 2 Te 3 layers were epitaxially grown by molecular beam epitaxy (MBE) on commercial silicon‐on‐insulator SOI(111) substrates. Using a spin‐coating nail‐polish layer over the Bi 2 Te 3 surface to protect it during the fabrication process, a sacrificial layer (buried oxide layer) was selective wet‐etched using a hydrofluoric acid solution. Post‐transfer, high‐resolution x‐ray diffraction measurements confirm that the transfer process preserves the high crystalline quality of the Bi 2 Te 3 layer. Finally, scanning tunneling microscopy indicates well‐defined terraces, demonstrating that the transfer procedure preserves the surface morphology, while scanning tunneling spectroscopy shows band gap values along the surface of the transferred Bi 2 Te 3 layer in good agreement with values expected for Bi 2 Te 3 semiconductor material. Our results point towards integration between topological insulators and already established technological platforms based on silicon membranes.