Beam Assisted Nanowire Growth

01.01.2010 - 31.07.2013
Research funding project
Over the past decade, one-dimensional nanostructures have been proven as powerful building blocks in active nanometer-scale devices. Aside from carbon nanotubes, nanowires (NWs) are one of the most promising approaches considered for scaling down optic-, electronic-, magnetic- and sensor devices. Low-dimensional nanostructures are usually fabricated using either a top down or a bottom up strategy. The former technique is extremely flexible, but suffers from limitations in minimum feature size and uniformity. The latter one, utilizing spontaneous self-ordering effects, is limited by the broad size distribution and the lack of control of the positioning of the self-organized nanostructures. Both ease and reproducibility of the processes involved are key factors for its practical use. In this context the discovery of the appearance of nanostructures induced by ion bombardment has attracted growing interest. In particular resist-less focused ion beam (FIB) techniques are most suited for the combination of top-down structuring with selective bottom-up self-assembling techniques. One of the most recent topics in FIB-solid interaction is, as erosion proceeds, the evolution of self-organized nanoscale pattern on solid surfaces. The diameters of these nanostructures are comparable to the sizes of biological and chemical species, and thus intuitively represent excellent primary transducers for producing signals that ultimately interface with macroscopic instruments. Additionally, nanostructure based sensors exhibit a fast response with a substantially higher sensitivity and selectivity than polycrystalline and crystalline bulk film based sensors. As NWs show up a high surface-to-volume ratio the impact of the ambient atmosphere on the conducting behaviour is extreme. Such sensors could be much smaller than standard optical-based detectors and simpler to use. Thousands of sensors could be packed into a hand-held device, which could produce results almost instantaneously. Based on previous own research this work advances towards new directions of FIB induced NW synthesis and their integration in CMOS compatible sensor prototypes. Initially, we will explore the nanopattern formation due to exposure with a Ga-FIB, several other ion beam species, beams of multi-charged ions as well as a novel fullerene source. In the same way we will investigate the capability of these methods for NWs formation. By means of a detailed research plan, a series of ion beam-material combinations will be successively investigated and evaluated to achieve three main goals: (i) to gain basic understanding of ion beam induced self assembling processes (ii) to develop suitable processes for the reproducible formation of NWs (iii) to develop suitable processes for CMOS compatible NWs formation. In a second step we will integrate individual as well as assemblies of NWs in resitivity type gas sensors and nanoscale pH-probes. For this purpose several aspects of contact formation, post-synthesis treatment such as annealing or enwrapping of the NWs by atomic layer deposition will be investigated. A CMOS compatible self-aligned processesing of the resitivtiy type gas sensor and nanoscale pH-probe are under consideration. The near-term relevance of this project is of a scientific nature. The project specific FIB generated nanopattern can be considered as primary tools for the exploration of the physics and the chemistry on the few-nanometer scale. Moreover, to the best of our knowledge no attempts have been published regarding the integration of such NWs into prototype devices.

People

Project leader

Project personnel

Institute

Grant funds

  • FWF - Österr. Wissenschaftsfonds (National) Austrian Science Fund (FWF)

Research focus

  • Non-metallic Materials: 10%
  • Special and Engineering Materials: 20%
  • Nano-electronics: 25%
  • Surfaces and Interfaces: 20%
  • Modeling and Simulation: 10%
  • Materials Characterization: 15%

Keywords

GermanEnglish
Fokussierte Ionenstrahlenfocused ion beam
Nanodrähtenanowire
Gassensorgas sensor
Mikroskalige pH Sondemicroscale pH sensor

Publications