Nanopatterning of mica surface under low energy ion beam sputtering

Abstract

Irradiation of crystalline muscovite mica samples by 500 eV Ar+ ions at different incident angles can induce significant surface morphological variations. A periodic ripple pattern of nano-dimensions forms in the angle window 47°-70°. On the other hand, tilted conical protrusions develop on the surface at grazing incidence angles around 80°. From the derivative of the topographic images the distribution of the side-facet slopes in the ion incidence plane are measured, which is found to be strongly related to the pattern morphology. Additionally, it has been shown that, for the ripple structures, the base angles can be tuned by changing the ion fluence. An asymmetric sawtooth profile of the ripples obtained at low fluence is transformed to a symmetrical triangular profile at high fluence. As the slopes are found to be small, the pattern formation is not provoked by the gradient-dependent erosion mechanism rather it is the general effect of the curvature-dependent sputtering phenomena.

Tailoring and investigation of surface chemical nature of virgin and ion beam modified muscovite mica

“…In addition, a weak peak of C is observed due to surface contamination or absorption of environmental carbon. The presence of all the elements in the virgin mica was also previously reported . The peak intensities of different elements change for both Ar + and N + bombardment (Figure A) due to the differential sputtering rate of mica elements.…”

“…The large depletion of positively charged K ions of the top layer of the mica surface by ion bombardment leads to adsorb hydrocarbon when the surface is exposed in the ambient atmosphere. The K depletion and C adsorption on mica after ion bombardment were also previously observed . The high‐resolution XPS core level spectra of C 1s for the virgin as well as Ar + and N + bombarded mica are shown in Figure A‐C.…”

“…Muscovite mica is a naturally available mineral having a crystalline and layered structure with alternating negatively charged aluminosilicate and positively charged K layers . Due to the layered structure, it can be easily cleaved to get an atomically flat, transparent, and hydrophilic surface, which is used in many fields of atomic and molecular scale studies, such as atomic force microscope calibration, supported lipid bilayer formation, DNA research, etc.…”

“…Various chemical treatments and thin film deposition techniques are followed to control the adhesion properties of mica surface. The energetic ion bombardment on mica substrate is very interesting, as it can change the chemical nature of surface in a controlled way as well as forms a well periodic pattern in nanoscale . However, the studies of surface chemistry of a virgin and an ion or plasma‐treated mica are rare in the literature .…”

Investigation of ion beam induced nanopattern formation near the threshold energy

“…These observations are consistent with the earlier data reported for 500 eV Ar þ on mica. 16 Both the threshold incidence angle h c and the critical angle of pattern rotation appear to be independent of the projectile energy. Figure 2 presents the phase diagram of patterns formed on Ar þ ion bombarded mica surfaces as a function of ion energy E and incidence angle h. Each morphological pattern is marked by a typical symbol.…”