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In this work, we present experimental results showing optical absorption enhancement of silicon wafer through etching and metal/metal-oxide nanolayers deposition. Black silicon nanograss were fabricated from single crystalline silicon by reactive ion etching, and ZnO, Pt, and CeO2 nanolayers were deposited through atomic layer deposition as well as magnetron sputtering. The resulting structure exhibits less than 8% reflection over broadband solar spectrum. The fabricated structures are analyzed by scanning electron microscope, focused ion beam milling slice and view and transverse electron microscope sample preparation. The results are compared to finite difference time domain simulations based on the actual fabricated structures. A study of the influence of various parameters on the geometry of the fabricated micro and nanostructures and the corresponding change in optical properties is also presented. Applications of such highly absorbing metamaterials to solar photocatalysis is discussed.

Nanowires of Au and Cu were fabricated using a top–down method in which focused ion beam (FIB) milling process has been used. The width of the fabricated nanowires has been kept in the range of 45 to 300 nm and the length in the range of 2–10 μm. In situ electrical measurements of the nanowires were carried out. The resistivities of these wires are found to be higher (five to nine times larger than their bulk values). These results have been understood on the basis of increase in the electron surface scattering due to one-dimensional confinement of the electrons. Also, other effects such as nanogap formation in the range of 40 nm to few hundreds of nanometers, structural changes of the wires, increase of current density with time at constant applied voltage, etc. have been observed during measurements.

Estimation of temperature rise during focused ion beam irradiation is of immense importance, since it affects various processes related to micro-machining and deposition. When ion beam impinges on a surface, it transfers its kinetic energy by way of electronic excitations and collisions, which eventually gets converted in the form of heat leading to rise in local temperature. This temperature rise affects and governs the properties of the machined region. The temperature rise can be calculated on the basis of energy deposition and heat transfer. However, there are very few reports on the measurement of such local temperature rise which lasts for very short time. We have designed and fabricated nanothermocouples of Pt–W to monitor local temperature rise (i) near a microheater and (ii) in the close proximity of an intense focused ion beam spot on a substrate. The junctions having size of 100 nm × 100 nm have been fabricated using focused ion beam chemical vapor deposition (FIB-CVD). The nanothermocouples have shown a fast response to the changes in temperature. These nanothermocouples can find useful applications in thermal characterization of nanomaterials and for understanding of temperature mediated phenomena in the samples treated under directed energy deposition processes, e.g. ion, laser and electron beam treatment.

We report a new method of generating nano and micro patterns using focused ion beam (FIB) induced adhesion. The method utilizes selective irradiation of thin metallic films grown on substrates by focused ion beam followed by peel off. After peel off of the irradiated thin film it is observed that the ion beam scanned portions are retained on the substrate, creating nano and micro patterns. The method is suitable for materials of which the adhesion to the substrate can be improved by ion bombardment. The phenomenon has been demonstrated by creating gold nano patterns of different shapes and sizes ranging from 500 nm to 5 μm on SiO2–Si substrate using 10–30 keV Ga FIB at beam currents up to 10 pA. The mechanism involved in the process has been discussed. The technique could be utilized to prepare micro and nano patterns of thin films deposited on an appropriate substrate for optical, plasmonic and sensor related applications.

Metallic nanowires (NWs) are the key performers for future micro/nanodevices. The controlled manoeuvring and integration of such nanoscale entities are essential requirements. Presented is a discussion of a fabrication approach that combines chemical etching and ion beam milling to fabricate metallic NWs. The shape modification of the metallic NWs using ion beam irradiation (bending towards the ion beam side) is investigated. The bending effect of the NWs is observed to be instantaneous and permanent. The ion beam-assisted shape manoeuvre of the metallic structures is studied in the light of ion-induced vacancy formation and reconfiguration of the damaged layers. The manipulation method can be used for fabricating structures of desired shapes and aligning structures at a large scale. The controlled bending method of the metallic NWs also provides an understanding of the strain formation process in nanoscale metals.

Focused Ion Beam (FIB) is one of the state of the art micro/nano fabrication tools. It adopts both bottom-up and top-down approaches to generate micro/nano structures and the biggest advantage of FIB lies in its maskless fabrication capability. The efficacy of the machine is now well proven among the scientific community. Modern FIB systems offer highly focused and precised beam of ions, which are effectively used for fabricating precised, high aspect ratio micro/nano structures.

Ion induced bending is a promising controlled technique for manipulating nanoscale structures. However, the underlying mechanism of the process is not well understood. In this letter, we report a detailed study of the bending mechanism of Si nanowires (NWs) under Ga+ irradiation. The microstructural changes in the NW due to ion beam irradiation are studied and molecular dynamics simulations are used to explore the ion–NW interaction processes. The simulation results are compared with the microstructural studies of the NW. The investigations inform a generic understanding of the bending process in crystalline materials, which we suggest to be feasible as a versatile manipulation and integration technique in nanotechnology.

Electrodes with nano-scale gaps have been fabricated using metallic nano-wires, derived via milling of thin films with focused ion beam (FIB) and passing current ~1012A/m2. Their I-V characteristics measured at a pressure ~10−6 mbar are shown to follow Child-Langmuir law or Fowler-Nordheim field emission depending upon the gap.

We report that during focused ion beam chemical vapor deposition (FIB-CVD) the effect of deposition is not limited to the area where the ion beam scanning takes place but occurs on regions which are out of sight of the incident beam and extends up to several micrometers away from the specified site. This phenomenon has deleterious effects, especially when the nanocontacts are fabricated for the electrical characterization of the nanodevices. The deposition occurs into the gap between the contact pads and acts as a resistance in parallel with the resistance of the nanostructure to be measured. The extended deposition has been explained on the basis of molecular cracking of the precursor gas molecules induced by forward scattered Ga ions, and appropriate measures to remove the effect have been suggested.

Precise metallic nanogap structure is fabricated on a glass substrate by using a 30 keV focused Ga ion beam. While investigating the I-V behavior of the nanogap structure, tunneling through the substrate has been found to play a vital role in the electrical transportation process. Substrate breakdown occurs at a certain applied voltage and a metal vapor state is initiated through intense heat generation at the nanogap region. The experimental observation confirms the role of the substrate in the explosion process. Metallic spherical particles are formed during cooling/condensation of the metal vapors or splashing of the liquid droplets showing a wide distribution of size from few tens of nanometers to few microns.

Electron-and ion-induced bending (EIB/IIB) phenomena have been studied in self-supported polycrystalline metallic and metal-amorphous bilayered nanocantilevers. The experiments reveal many interesting facts regarding electron/ion-matter interaction, which builds a proper foundation for the understanding of the phenomenon. The mechanism for bending of metallic cantilevers has been proposed to be primarily due to void-induced stress generation during ion beam irradiation. On the other hand, thermal effects have been found to play the dominant role in the case of bending of bilayer (amorphous-metal) nanocantilevers. The instantaneous, reversible, highly controllable and permanent nature of the process has been exploited to fabricate several complicated nanostructures in three dimensions. IIB of the fabricated cantilevers is shown to have a high precession mass sensing aptitude, capable of detecting a change in mass of the order of femtograms.

Novel methodologies to overcome some of the difficulties in standard deposition procedures in focused ion beam (FIB) systems to fabricate 3D nanostructures are described. The geometrical restriction put on by the position of electron and ion columns and the precursor gas needles in a conventional FIB chamber, complicates the 3D fabrication process. As case studies, wide vertical walls and overhanging bridge-type structures of tungsten are fabricated. The overhanging bridge-type structure of tungsten can be used as a nanofilament for producing heat within a few micrometre distances. The heat, produced in the filament, is sensed by a tungsten-platinum nanothermocouple fabricated underneath the filament.

A nano-mechanical switch has been fabricated and its switching action has been demonstrated. The device utilises the phenomenon of bending of Pt nanopillars and cantilevers induced by focused ion beam (FIB). Two skew Pt pillars with equal lengths and different cross-sections have been fabricated subtending an angle of approximately 100° with each other using FIB-chemical vapour deposition (CVD). One of the pillars is initially made to bend towards the adjacent pillar to achieve a physical contact with it, and then is bent in opposite direction from it. The pillar has been bent along the desired orientation by appropriately choosing the ion beam irradiation directions. The switching action has been demonstrated by applying constant voltage across the Pt pillars and measuring the current passing through it, as a function of time during ion beam scanning. These nano-mechanical switches would find useful applications during the in-situ electrical characterisation of micro- and nano-structures fabricated by FIB.

The authors report a detailed study on the deposition because of scattered Ga ions during the focused ion beam chemical vapour deposition (FIB-CVD). The scattered ions strike the surface of the substrate nearby the base of the structure being fabricated by the primary ions, and decompose the organometallic molecules adsorbed on it, leading to the broadening of the base. Such deposition is dominant up to several micron distances from the base of the nanostructures depending on the primary ion flux. During the FIB-CVD, similar deposition occurs on the surface of nearby pre-fabricated structures, situated up to a few micrometre distances from the nanostructure being fabricated. The scattered-ion-induced deposition complicates the fabrication of complex 3D structures. The authors present the parametric dependence of the deposition because of scattered Ga ions during FIB-CVD.