Monolithic Integration of Nanowires Enabling Hybrid Devices

15.12.2008 - 31.08.2012
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, semiconducting nanowires (NWs) are one of the most promising approaches considered for scaling down optic-, electronic-, magnetic- and sensor devices. Moreover, in comparison to other nanotechnology device option, semiconductor NWs may have the potential to be implemented on an existing semiconductor infrastructure and can thus benefit from continous improvements in CMOS technology. Apart from device shrinking, the monolithic integration of the (superior) III¿V semiconductors which are particularly attractive for optoelectronic device applications into the mature silicon technology combine the best parts of different technologies and will lead to enhanced functionality. Carrier confinement in heterostructures provides further an opportunity to increase the efficiency of radiative recombination of electrons and holes. Fundamental issues such as lattice and thermal expansion mismatch and the formation of antiphase domains which have prevented the epitaxial integration of III¿V with group IV semiconductors could be avoided by a nanowire approach. By reducing the contact area the crystal lattice of the III¿V material will be elastically deformed near the interface, and due to the small dimension the strain could be accommodated at the nanowire surface. The monolithic integration of hierarchical NW heterostructures with Si devices and the electrical and optical characterization of these functional building blocks is the final goal of this project. Initially, we will explore the well controlled formation of NWs and heterostructures combining LPCVD and MBE techniques. The control over the so called vapor-liquid-solid (VLS) NW growth is mediated through the usage of nanoscopic metal templates. In a second step we will integrate individual NWs and defined assemblies of NWs in test modules which enable to extract their fundamental electrical and optical properties being a significant step for the exploitation of such structures as a platform for novel electronic, spintronic or magneto-optic devices and sensor applications. For this purpose several aspects of contact formation to the 1D nanostructures as well as abrupt heterojunction formation have to be solved. Two different, partly self-aligned processes of test module formation mainly based on SOI technology are under consideration. By means of a detailed research plan, a series of material combinations will be successively processed and evaluated to achieve three main goals: (i) to develop suitable processes for the formation of NW heterostructures (hybrid systems, vertical and radial heterostructures and hierarchical branched structures) (ii) to gain basic understanding of hetero-junction interface as well as metal/nanowire contact properties (iii) to develop suitable measurement methodologies to qualitatively as well as quantitatively explore electrical and optical characteristics of NW/Si-technology hybride systems and thereby allow a benchmarking. The growth of NW heterostructures and integration in the various test modules will be accompanied by analytical support activities (HRTEM, EDX, EELS, AES, SIMS, XRD,¿) providing feed-back for process optimization. Aside of the scientific output, a major aspect of the proposal is to provide young researchers and especially PhD candidates the opportunity to take part in a project on nanotechnology will allow them to develop a scientific independence and to gain hands-on experience in a prospective area in the core of future science.

People

Project leader

Project personnel

Institute

Grant funds

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

Research focus

  • Non-metallic Materials: 5%
  • Biological and Bioactive Materials: 10%
  • Photonics: 10%
  • Quantum Metrology and Precision Measurements: 5%
  • Nano-electronics: 30%
  • Sensor Systems: 10%
  • Design and Engineering of Quantum Systems: 10%
  • Surfaces and Interfaces: 10%
  • Materials Characterization: 10%

Keywords

GermanEnglish
elektrischer transportelectrical transport
halbleitersemiconductor
nanodrähtenanowires
heterostrukturenheterostructures

Publications