Joanna Millunchick

Professor

joannamm@umich.edu

2014 HH Dow

T: (734) 647-8980

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Focused ion beam creation of III-V semiconductor nanostructures

Focused ion beam (FIB) irradiation and patterning of semiconductors has been demonstrated as a method for the creation of unique nanostructures. The III-V semiconductors in particular show a wide range of responses to FIB irradiation depending on material and exposure conditions. We have characterized the 30 kV normal incidence FIB response of GaAs, InAs, InP, and AlAs. As has been previously observed by other researchers, under normal incidence 30 kV FIB irradiation GaAs, InAs, and InP all form group III rich droplets. However, by varying exposure conditions or by starting with III-V heterostructures other structures may be produced as well. We have found that under certain FIB conditions irradiation of InAs films grown on InP can be used to produce a variety of nanostructures besides group III droplets, including nanoscale semiconductor spikes. These semiconductor spikes form a heterojunction with the substrate, and their location may be controlled and templated. Work is currently underway to characterize the structural, chemical, and electrical properties of these semiconductor nanospikes.
Highlights (Click an image for more information)
  • TEM of focused ion beam created III-V nanospike

    Bright-field transmission electron microscope (TEM) image of an InAs nanospike on an InP substrate.  The nanospike was created by exposing an InAs film grown on an InP wafer to focused ion beam (FIB) irradiation under specific conditions.  A group III cap is visible at the top of the spike, while the crystalline core is visible as the darker region at the center of the spike.

  • SE image of focused ion beam created III-V nanospikes

    Secondary electron image of InAs spikes on an InP substrate.  These nanospikes were created by exposing an InAs film grown on an InP wafer to focused ion beam (FIB) irradiation under specific conditions.