Nanostructured germanium prepared via ion beam modification

Abstract

Nanostructured" germanium (Ge; also known as "voided," "porous," "nanoporous," "cratered," and "honeycomb" Ge) created via ion beam modification has been studied for many years. This work reviews the progress made in studying and characterizing the nanostructured morphology, particularly via the use of experimental techniques such as scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Specifically, the empirical observations of the structural evolution of Ge as a function of ion beam modification conditions are discussed with added emphasis placed on quantification of the microstructure. The experimental observations and microstructure quantification are further discussed in terms of the implications for proposed formation mechanisms of the nanostructured morphology. Potential uses of the nanostructured morphology in chemical sensor and energy storage applications and suggested future lines of research to further the fundamental understanding of nanostructuring in Ge using ion beam modification are also presented.

Role of ion mass on damage accumulation during ion implantation in Ge

“…However, compared to the implant damage evolution during thermal annealing and its role on dopant diffusion and activation [3][4][5][6], the as-implanted damage in Ge has received much less attention [7][8][9][10]. Relatively few studies have been performed in order to investigate the influence of the implantation parameters on the induced lattice damage.…”

Formation of TiO2 nanorods by ion irradiation

“…In Ge, the material must be amorphous prior to the irradiation-induced porosity. 12 However, in TiO 2 , porosity precedes complete amorphization, which suggests that N 2 bubbles may play a crucial role in the formation of nanopores and the nanorod structure.…”

“…In particular, for a few different types of semiconducting materials, such as indium antimonide (InSb), galliumantimonide (GaSb), and gallium nitride (GaN), ion beam modification under appropriate conditions can result in complete structural decomposition of a material to a porous microstructure consisting of nanopores. 12 Recently, Romero-Gomez et al obtained various surface nanostructures on anatase TiO 2 thin films, such as cellular defect structures or nanorod surface patterns aligned with the angle of incidence of the beam by ion irradiation. 13 However, the formation mechanism of the surface nanostructures induced by ion irradiation is still a controversial issue.…”

Nanostructuring Germanium Nanowires by In Situ TEM Ion Irradiation

“…For this purpose, it has been proposed in the literature to use ion beams to nanostructure several semiconductor materials such as gallium antimonide, indium antimonide, gallium nitride, and germanium. [ 22–29 ] Indeed, it is reported that these materials can become nanoporous when subjected to ion bombardment. [ 22–29 ] The use of ion beams to induce nanopores in germanium is attractive as nanoporous germanium is interesting for integration in photovoltaic cells, batteries, microelectromechanical systems or gas and bio sensors.…”

“…[ 22–29 ] Indeed, it is reported that these materials can become nanoporous when subjected to ion bombardment. [ 22–29 ] The use of ion beams to induce nanopores in germanium is attractive as nanoporous germanium is interesting for integration in photovoltaic cells, batteries, microelectromechanical systems or gas and bio sensors. [ 22,30,31 ]…”