Methods of forming metal oxide thin films and related structures are provided. One embodiment of the methods includes conducting a plurality of cycles of deposition on a substrate. Each cycle includes supplying oxygen gas and an inert gas into a reaction space substantially continuously during the cycle. A metal precursor is supplied into the reaction space for a first duration. The metal precursor is a cyclopentadienyl compound of the metal. After the metal precursor is supplied, the continuously flowing oxygen gas is activated for a second duration to generate a plasma in the reaction space. The cycle is conducted at a temperature below about 400° C. The methods can be performed after forming a structure on the substrate, wherein the structure is formed of a material which is physically and/or chemically unstable at a high temperature.