Robust Surface State Transport in High Target Utilization Sputtering (HiTUS) Grown Bi _0.85 Sb _0.15 Thin Films

Abstract The growth of topological insulator (TI) thin films of Bi 0.85 Sb 0.15 on Si/SiO 2 (100) substrates via a high target utilization sputtering (HiTUS) system is reported. From transport measurements, crystallography, and measurements of surface roughness, it is determined that these HiTUS‐deposited, annealed thin films have properties comparable to films grown via molecular beam epitaxy (MBE). In this study, 12 nm thick Bi 0.85 Sb 0.15 thin films are deposited and the sputtering energy and annealing conditions are varied across three generalized energy regimes: low energy, high energy, and high energy annealed. High‐energy films annealed at T = 175 ° C for 1 h crystallize into the trigonal R3M space group with a (003) surface orientation and exhibit robust weak antilocalization (WAL) at T = 3 K with a magnitude greater than reported in literature. The Dirac fermion model is used to fit to the WAL cusp and derive a Fermi velocity of 57.1 ± 0.2 km s −1 , in good agreement with what has been reported from angle resolved photoemission spectroscopy (ARPES) measurements of Bi 0.9 Sb 0.1 single crystals. Additionally, evidence of surface state transport in Bi 0.85 Sb 0.15 thin films grown without any annealing steps or heat added during growth is reported.