Atomic layer deposition with passivation treatment

1. A method comprising:

(1) performing an atomic layer deposition cycle including

(a) introducing precursors into a deposition chamber housing a substrate to deposit a material on the substrate, wherein the substrate is carbon, the material is Pt, and the precursors comprise:

one or more organometallic Pt precursors;

an oxidative precursor comprising oxygen plasma or ozone introduced after the one or more organometallic Pt precursors; and

a reductive precursor comprising hydrogen gas or hydrogen plasma introduced after the oxidative precursor; and

(b) introducing a passivation gas into the deposition chamber wherein the passivation gas is carbon monoxide, and the carbon monoxide adsorbs onto a surface of the Pt; and

(2) repeating (1) a plurality of times to form a film of Pt, wherein:

the carbon monoxide adsorbed onto the surface of the Pt forms an intermediate species; and

the adsorption energy of the one or more organometallic Pt precursors to the intermediate species is greater than an adsorption energy of the one or more organometallic Pt precursors to the substrate,

wherein the film of Pt has a mass loading of about 0.3 μg/cm 2 and a mass activity of about 1.0 A/mg Pt to about 1.3 A/mg Pt to about 3 μg/cm 2 .

2. The method of claim 1 , wherein a surface coverage of the substrate by the film is at least 30%, and the film has an average thickness in a range from 1 atomic layer to 5 atomic layers.

3. The method of claim 1 , wherein the oxidative precursor consists of ozone.

4. The method of claim 1 , wherein the reductive precursor consists of hydrogen gas.

5. The method of claim 1 , wherein the film has an average thickness in a range from 1 atomic layer to 3 atomic layers.

6. The method of claim 1 , wherein the film has an average thickness in a range from 1 atomic layer to 2 atomic layers.

7. The method of claim 1 , wherein the film has a surface roughness of no greater than 80% of its average thickness.