“…As shown in Figure 5 [39], nucleation density decreases with increasing particle size of diamond abrasive paste in the polishing pretreatment ( Figure 5(a)), but increases with increasing particle size in the ultrasonic scratching pretreatment ( Figure 5(b)). Generally, however, the optimal size of abrasive particles depends on pretreatment methods, deposition processes, growth conditions, and nature of substrate materials [72,77,[111][112][113][114][115][116]. The size and physical properties of the abrasives used for scratching pretreatment are summarized in Table 6.…”