Vapor deposition processes

A deposition assembly for depositing elemental metal or semimetal on a substrate comprising:

• one or more reaction chambers constructed and arranged to hold the substrate;
• and
• a precursor injector system comprising:
• a first vessel storing a metal or semimetal precursor;
• and
• a second vessel storing a reducing agent comprising a cyclohexadiene compound selected from compounds of formula (I),
• wherein each of Z1 and Z2 is independently selected from a group consisting of CR11 and N, and wherein each of R1 to R11 is independently selected from a group consisting of H, C1 to C7 linear or branched alkyl, C6 to C10 aryl and C6 to C14 heteroaryl, and
• wherein the deposition assembly is constructed and arranged to provide the metal or semimetal precursor and the reducing agent via the precursor injector system to a reaction chamber, of the one or more reaction chambers, in a vapor phase to deposit metal or semimetal-containing material on the substrate.