Atomic Layer Deposition and Thermal Transformations of Aluminum-Vanadium Oxide Thin Films

Aluminum-vanadium oxide (Al x V y O z ) nanofilms were obtained by atomic layer deposition using trimethylaluminum, vanadium oxychloride, and water. The growth of films was studied in situ by quartz crystal microbalance and ex situ by deposition on Si(100). At a deposition temperature of 115°C, linear growth of films and a self-limited nature of surface reactions were observed. Two types of amorphous films, Al 2.1 V 0.4 O 4.1 Cl 0.1 and Al 1.1 V 0.9 O 4.4 Cl 0.2 , were obtained. The thermal treatment of Al 1.1 V 0.9 O 4.4 Cl 0.2 films in the temperature range from 500 to 550°C in air resulted in the Al 2 O 3 –V 2 O 5 heterostructured coatings. Annealing at 500°C led to spontaneous formation of crystalline V 2 O 5 through the formation of supercooled vanadium oxide nanodroplets. At 550°C, the formation of V 2 O 5 crystalline nanofilm and single-crystal nanowires was observed. Nanoscale islands of triclinic AlVO 4 were obtained by heat treatment at 630°C.