coatings Article Improving the CO and CH4 Gas Sensor Response at Room Temperature of α-Fe2O3(0001) Epitaxial Thin Films Grown on SrTiO3(111) Incorporating Au(111) Islands Aída Serrano 1,2,3,* , Jesús López-Sánchez 2,3,4, Iciar Arnay 2,3, Rosalía Cid 2,3,5, María Vila 2,3...