Arun Kumar; Raimondo Cecchini; Lorenzo Locatelli; Claudia Wiemer; Christian Martella; Lucia Nasi; Laura Lazzarini; Roberto Mantovan; Massimo Longo
Bi2Te3 is attracting a renewed interest, due to its topological insulator properties; however, even using advanced physical and chemical deposition techniques, the growth of high-crystal quality layers on substrates allowing its technological employment, such as Si, is very challenging, due to the structural complexity of Bi2Te3. In this work, we present the optimized large area growth of topological insulator Bi2Te3 epitaxial layers on un-buffered i-Si (111) substrates via Metal-Organic Vapor Phase Epitaxy (MOVPE), which is of crucial importance for future integration into CMOS compatible spintronic devices. We found that the key to maximizing the layer quality requires a balanced control of the reactor pressure (P), growth temperature (T), and growth time (t). Within a proper parameter window, the grown Bi2Te3 thin layers are crystalline, stoichiometric, and highly uniform, also at the local scale. They exhibit a rhombohedral crystalline structure, and they are  out-of-plane oriented on the i-Si (111) substrate. Low temperature magnetoresistance measurements revealed clear Weak Antilocalization (WAL) effects, demonstrating that the optimized MOVPE – grown Bi2Te3 is a topological insulator, hence opening further possibilities for its technology-transfer to innovative devices.