AFM images were recorded for EPI films deposited at different substrate temperatures to observe any differences in the film morphology. Fig. 1 shows AFM images of nominally ∼100 nm thick films prepared at substrate temperatures of 200, 300 and 350 K. Unless otherwise stated, all results discussed below refer to samples with a thickness of 100 nm. All samples show fully covered substrates with a certain degree of roughness in the multi-domain films. The different substrate temperatures only induce minor differences in the film morphologies. For example, it can be seen that the films prepared at 300 and 350 K are smoother than those prepared at 200 K. Also, a small difference in the island/domain size is also noticeable, with the films prepared at 350 K having larger islands than those prepared at lower temperatures. The observed morphologies are consistent with previous morphological studies of EPI thin films.5