Time-evolution growth of Ag nanolayers on differently-passivated Si(001) surfaces

Abstract

The growth and evolution of Ag nanolayers on differently-passivated Si͑001͒ substrates at ambient condition have been studied. Initial compactness and smoothness of Ag nanolayer on the H-passivated Si͑001͒ surface are found better compared to those on the Br-passivated Si͑001͒ surface, which can be understood considering surface free energy and surface mobility of the passivated surfaces. As the time passes, the growth of dewetted three-dimensional ͑3D͒ islandlike structures ͑Volmer-Weber-type mode͒ from comparatively wetted Ag nanolayer ͑Stranski-Krastanov-type mode͒ is evident at ambient conditions. Such evolution of growth is through dewetting ͑related to the change in the interfacial energy due to the oxide growth͒, migration, and coalesce of Ag, which can even produce large epitaxial ͓Ag͑001͒/Si͑001͔͒ 3D islands on H-passivated Si͑001͒ surface. The growth rate, size, number density, and epitaxy/nonepitaxy of 3D islands are different for different passivated surfaces. These differences can be realized considering the growth time of oxide ͑i.e., instability of passivated surface͒, in-plane inhomogeneity of interfacial energy ͑i.e., inhomogeneous nature of passivation͒, and in-plane diffusion of Ag on the passivated surfaces.

Role of substrate in melting behavior of Langmuir–Blodgett films

“…Confinement effect, large surface to volume ratio and interface energies of nano-materials is the probable reasons behind this. Substrate surface condition also plays crucial role in the growth and stability of nano-layer on it [11,12]. A promptly implemented method to improve the film quality is to alter the surface energy of the substrate to boost a better film growth.…”

“…A promptly implemented method to improve the film quality is to alter the surface energy of the substrate to boost a better film growth. The surface and interface energies influence the structural properties significantly, because large surface is available to react [12][13][14][15]. As the LB film contains amphiphilic molecules, having both hydrophobic and hydrophilic parts, its structure can be improved by changing the surface nature of the substrate.…”

Reorganization of Au nanoparticle Langmuir-Blodgett films on wet chemically passivated Si(001) surfaces

“…Substrate surface condition plays an important role in the growth and stability of any nanolayer on it. [26][27][28] Nature of the substrate surface can be modified by passivating with foreign atomic layer (such as H, Br, Cl, etc.) or by growing self-assembled monolayers (of say silane).…”

“…This essentially modifies the surface-free energy or polar-nonpolar nature of the substrate surface and accordingly, wetting-dewetting or hydrophilicity-hydrophobicity of the surface can be tuned. [27][28][29][30][31][32][33] Strong influence has already been observed in the growth and stability (time-evolution in-plane and out-ofplane structures) of the metal (Ag, Au) nanolayers and of the nickel-arachidate (NiA) LB film on differently passivated Si substrates. 27,34 For the fatty-acid salt molecules, like NiA, presence of both hydrophilic metal-bearing headgroup and hydrophobic hydrocarbon tail affects the structure and stability of the deposited films strongly.…”

Prolonged reorganization of thiol-capped Au nanoparticles layered structures

“…16 Substrate surface conditions also play an important role in the growth and stability of any nanolayer on it. [24][25][26][27] For the organic capped nanoparticles, which are effectively hydrophobic in nature the growth, structure and stability on differently passivated Si surfaces have been studied. 28 Differently passivated Si surfaces have different hydrophilic/hydrophobic nature, which effectively controls the growth and stability of the nanoparticle films.…”