For example, ZnO NWs showed a larger diameter as well as lower density with the increased size of droplets [9]. To date, various NWs such as Si, Ge, ZnO, GaN, GaAs, InP, and InAs have been fabricated by the Au droplet-assisted VLS approach [9–16]. In the meantime, due to

their unique HDAC inhibitor properties and applications, such as localized surface plasmonic resonance, catalysis, quantum size effect, and bio-sensing, Au droplets have drawn a lot of research attention and have been demonstrated on diverse surfaces including Si, sapphire, SiO2, GaN SiC, and polymeric substrates [17–25]. As a common semiconductor with a GANT61 direct band gap, GaAs is widely used in light-absorbing and light-emitting devices, and also various GaAs surfaces of different indices are often used in controlled

fabrication of nanostructures. For example, the cross-sectional shape of NWs can be determined by substrate indices such as a triangular shape on GaAs (111)A, trapezoid shape on GaAs (110), and hexagonal shape on GaAs (111)B Blebbistatin cost [26–28]. In addition, the resulting NWs on GaAs (111)B often showed stacking faults (SFs), and SF-free NWs can be successfully fabricated on GaAs (311)B and others [29–31]. This naturally puts the investigation on the Au droplets synthesized on a diverse GaAs index, which is an essential research topic in the fabrication of desired NWs. However, to date, systematic studies on Au droplets on type-B GaAs are still second deficient. In this paper, we thus demonstrate the fabrication of self-assembled Au droplets on various GaAs (n11)B, where n is 2, 4, 5, 7, 8, and 9 via the systematic variation of the Au deposition amount (DA). As an example, the simplified fabrication process of the self-assembled Au droplets on GaAs (211)B via the Volmer-Weber growth mode [32–34] is illustrated in Figure 1. Staring from the bare GaAs (211)B in Figure 1a, the surface still showed a quite smooth surface topography even after the 6-nm Au deposition as shown in Figure 1b,b-1. After a systematic annealing process, the resulting Au

droplets are shown with the 3-nm deposition in Figure 1c and 6-nm DA in Figure 1d. Under an identical growth condition, the self-assembled Au droplets show drastically different sizes and densities, and as a function of the DA, a gradual dimensional expansion including the average height and the average diameter was clearly observed while the average density swings over 2 orders of magnitude. On the various substrates utilized, a similar trend of the evolution process was clearly observed while showing minor index dependency. Figure 1 Illustration of self-assembled Au droplet evolution on GaAs (211)B as a function of deposition amount (DA). (a) Bare GaAs surface. (b) After 3-nm Au deposition. (c) Au droplets with 3-nm DA. (d) Au droplets with 6-nm DA.