Silver- and Gold-Ordered Structures on Single-Crystal Silicon Surface After Thermal Deposition

Vladimir Karbivskyy,Viktor Artemyuk,Love Karbivska

doi:10.1186/s11671-016-1291-2

Abstract

The formation mechanisms of Ag- and Au-ordered structures on single-crystal silicon (Si) (111) and Si (110) surfaces were researched using high-resolution scanning tunneling microscopy method. It was shown that different patterns of self-assembled nanostructures with very precise and regular geometric shapes can be produced by controlling process parameters of thermal metal spraying on the substrate. The surfaces of nanorelieves at each stage of deposition were researched, and the main stages of morphological transformation were fixed.Self-ordered hexagonal pyramid-shaped nanostructures were formed at thermal deposition of gold on the Si (111), whereas only monolayer hexagonal formation could be observed on the plane Si (110). Gold monolayer flake nanostructures were obtained under certain technological parameters.Atomically smooth Ag film cannot be obtained on the Si (111) surface by means of thermal spraying at room temperature. The formation of two-dimensional (2D) clusters takes place; heating of these clusters at several hundred degrees Celsius leads to their transformation into atomically smooth covering.The weak interaction between Ag multilayer coatings and substrate was established that allows to clear crystal surface from metal with reproduction of the reconstructed Si (111) 7 × 7 surface by slight warming. The offered method can be used for single-crystal surface protection from destruction.

Highlights

The production of nanostructures of metals on atomically clean surfaces of semiconductor single crystals is one of the main research areas for scientists who study the surface of materials and processes of thin film growth
Hexagonal pyramid formation over the entire area of the sample had different height and upper platform area due to the uneven flow of sorption particles on the crystal surface; Fig. 2 Gold nanostructures on Si (111) (a–e) and Si (110) (f–i) their coincidence was fairly often observed. As it has been previously shown [11], hexagonal pyramidal gold structures are stably obtained only on the Si (111) plane, while on Si (110) plane, we have obtained the structures shown in Fig. 2f, which are characterized by the hexagon without pyramid formation
It is established that the growth of nano-gold islands on the single-crystal silicon surface is determined by the flow of substances to the surface and from it

Summary

Introduction

The production of nanostructures of metals on atomically clean surfaces of semiconductor single crystals is one of the main research areas for scientists who study the surface of materials and processes of thin film growth. It is well known that the growth mechanisms of thin metal films on various substrates are described by three basic types of growth—two-dimensional (2D) method or layer-by-layer growth (Frank–Van der Merve growth), Karbivskyy et al Nanoscale Research Letters (2016) 11:69 in an atomically flat film Such transition from cluster organization to atomically smooth surface is observed only when the total number of layers is at least six monolayers (ML) [3]. There occurs a dependence of electron energy variation on the thickness, which comprises an electrostatic potential owing to the occurrence of the electric double layer with scattered electrons at the interface and the electrons oscillation along the direction of normal to the surface. The film tends to flatten out and acquires the atomically flat morphology

Methods

Results

Conclusion