Ar⁺-sputtered Ge (001) surface nanostructuring at target temperature above the recrystallization threshold

Abstract

Nanoscale pattern formation on Ge (001) surface by 500 eV Ar+ bombardment has been studied for a wide range of ion incidence angles at a temperature of 300° C. In the angular regime 0° to 65°, a fourfold symmetric topography forms which shows a remarkable transition into highly regular one-dimensional asymmetric pattern at grazing incidences, known as perpendicular mode ripples. The four-fold symmetric patterns are found to retain their symmetry under the concurrent substrate rotation during sputtering, while the ripples show degeneration into hole structure with a weak fourfold symmetric pattern. The dynamics of the observed patterns has also been investigated in a wide range of ion fluence from 1 × 1017 to 1 × 10 20 ions cm−2. The square topographies are found to be determined by Ehrlich–Schwoebel barrier induced diffusion bias driven growth process, whereas, the ripple formation implies the role of incidence ion beam direction.

Layer-by-Layer Pyramid Formation from Low-Energy Ar+ Bombardment and Annealing of Ge (110)

“…Once the surface forms large surface domains, which typically takes 8-16 cleaning cycles, additional cleaning cycles cause fewer changes to the surface. This is in contrast with other ion bombardment experiments, where increasing fluence caused an increase in surface roughness [12,[14][15][16]32].…”

Nanopatterning of the (001) surface of crystalline Ge by ion irradiation at off-normal incidence: Experiment and simulation

“…The interplay of these factors with effects of off-normal irradiation may be worth further investigations. In very recent work, Chowdhury and Ghose discussed patterning of crystalline Ge(001) surfaces resulting from ion irradiation at off-normal incidence angles and an azimuthal orientation of ϕ ion = 315 • [48]. While they investigated the pattern evolution with fluence and the effect of continuously rotating the sample, they did not approach their results from a theoretical viewpoint.…”

Self-Organized Tailoring of Faceted Glass Nanowrinkles for Organic Nanoelectronics

“…In this way, it is possible to obtain the growth of out-of-plane oriented facets under specific conditions, such as controlled deposition and/or ion irradiation of crystalline surfaces . More recently, very similar results have been achieved by irradiating semiconductor surfaces above their recrystallization temperature − enabling several seminal experiments in nanophotonics and photochemistry which exploit high-aspect ratio crystalline nanostructures (e.g., nanocones, nanopits) characterized by oriented ridges that register with the crystallographic planes. , However, this approach is intrinsically limited to high-quality crystalline materials, opening a crucial issue in view of cost-effective applications in optoelectronics and flexible organic electronics, which are generally based on transparent low-cost substrates. The possibility to fabricate faceted periodic patterns with controlled periodicity, height, and slope at the surface of low cost amorphous substrates thus represents an open issue to be addressed in view of technological applications.…”