“…Because selective growth is easily achieved at a relatively low temperature without a SiO 2 mask, it is easier to use BILE to obtain a smooth surface by protecting the sample from thermal roughing. However, use of BILE on (0 0 1) GaAs usually showed a relatively rough upper surface [13]. To improve the technique, we have studied the growth mechanism of BILE, and so far, we have found that the formation of facets on the lateral growth front controls the shape of BILE [14].…”