Unintentional F doping of SrTiO3(001) etched in HF acid-structure and electronic properties

► F substitutes for O in the surface layer of HF-etched and tube-furnace-annealed SrTiO3(001). ► The F is quite stable against annealing up to at least 850 K. ► Substitutional F does not dope the surface n-type. ► The surface Fermi level remains unpinned.