Fig. shows the comparison of SC between samples deposited for 60 min in three different deposition conditions, i.e., without Xe, with 100 sccm co-flow of Xe and with 100 sccm coflow of Ar. We maintained the total reactor pressure for all the experiments, allowing us to operate the processes at the same Knudsen number, facilitating a meaningful comparison. It can be observed from the scanning electron microscopy (SEM) measurements that the SC was improved from 0.71 to 0.97 when Xe co-flow was added. A control experiment with a co-flow of Ar, with atomic mass of 40 amu, i.e., lower than the TEB molecule, afforded a SC of 0.69, i.e., very similar result as without any co-flow of inert gas. This strongly suggests that it is not the inertness of Xe that enhanced the SC, but rather the atomic weight, in accordance with the hypothesis of competitive diffusion. We speculate that also a reduction of the surface residence time and enhanced desorption rate for reactive intermediates due to Xe flow can also contribute to such a diffusion enhancement.