title: Atomic layer deposition of nickel-cobalt spinel thin films.
abstract: We report the atomic layer deposition (ALD) of high-quality crystalline thin films of the spinel-oxide system (Co1-xNix)3O4. These spinel oxides are ferrimagnetic p-type semiconductors, and promising material candidates for several applications ranging from photovoltaics and spintronics to thermoelectrics. The spinel phase is obtained for Ni contents exceeding the x = 0.33 limit for bulk samples. It is observed that the electrical resistivity decreases continuously with x while the magnetic moment increases up to x = 0.5. This is in contrast to bulk samples where a decrease of resistivity is not observed for x > 0.33 due to the formation of a rock-salt phase. From UV-VIS-NIR absorption measurements, a change from distinct absorption edges for the parent oxide Co3O4to a continuous absorption band ranging deep into the near infrared for 0 < x ≤ 0.5 was observed. The conformal deposition of dense films on high-aspect-ratio patterns is demonstrated.
authors.affiliation: Department of Chemistry and Materials Science, Aalto University, Espoo, Finland. maarit.karppinen@aalto.fi.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hagen
authors.affiliation: Department of Chemistry and Materials Science, Aalto University, Espoo, Finland. maarit.karppinen@aalto.fi.
authors.forename: T S
authors.initials: TS
authors.lastname: Tripathi
authors.affiliation: Department of Chemistry and Materials Science, Aalto University, Espoo, Finland. maarit.karppinen@aalto.fi.
authors.forename: M
authors.identifier: http://orcid.org/0000-0003-1091-1169
authors.initials: M
authors.lastname: Karppinen