Excess precursors, reaction by-products and physiosorbed surface species should be removed and evacuated by purging the ALD system with inert gas, N2, in our experiments. To further study the influence of purge time and in the best possible attempt to mimic continuous CVD in our ALD reactor, we did InN ALD experiments with varied purge time. After the TMI pulse and the subsequent purge, the surface was exposed to NH3 plasma, which nitridized the surface and immobilized all In species. The surface morphologies of InN ALD grown with different purge times is then a reflection of the behavior of the adsorbed In-species on the surface. When 0.1 s purge time is used after the TMI pulse in a 320 °C deposition, a very high density (1.1×10 11 cm -2 ) of scattered particles is seen by top-view SEM (Fig. ). A longer purge of 2 s results in a reduced density (1.6×10 10 cm -2 ) of averagely larger particles (Fig. ). With a long purge time of 8 s, a high-density particle-like feature (7.5×10 11 cm -2 ) can be seen uniformly on the surface (Fig. ). The particle-like surface feature is likely due to a Stranski-Krastanov growth mode where 3D growth takes over after a critical thickness of approximately 1 nm. The particle density, particle size and inter-particle distance can be used to depict the distribution of adsorbed In-species on the surface, which changes with time, reflecting their mobility. According to our analysis, the average particle size increases from 5 nm to 16 nm (Fig. ) and the inter-particle distance also increases significantly (Fig. ) by increasing the purge time from 0.1 s to 2 s. The increase in diameter of particles and inter-particle distance with longer purge time is an indication that the physiosorbed In-species on the surface are mobile until they are immobilized by the NH3 plasma. According to the work by Muneshwar and Cadien, an ALD precursor pulse results in physiosorbed species, able to diffuse on the surface before being chemisorbed. With a long purge, all physiosorbed surface species should either chemisorb or desorb from the surface, leaving only chemisorbed In-species for nitridation. The growth rate per ALD cycle increases with increasing purge time; 0.1 s purge renders 0.22 Å/cycle, 2 s purge renders 0.31 Å/cycle and 8 s purge gives 0.41 Å/cycle as shown in Fig. . Such trend has previously been seen by Muneshwar and Cadien and suggests that the surface dynamics, producing chemisorbed species, is of very high importance for the film deposition. In addition, 8 sec is adequate for the purge time in our case as the growth rate becomes saturated (Fig. ). The SEM image shown in Fig. reflects the outcome of InN deposition with an adequate purge time to have, presumably, no physiosorbed In-species.