Archive – 2010

PhD-defense

I have successfully defended my PhD-thesis „Propagation of Light in Ensembles of Semiconductor Nanowires“ on 20th December 2010 at Eindhoven University of Technology.

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Nanoscale Free-Carrier Profiling of Individual Semiconductor Nanowires by Infrared Near-Field Nanoscopy.

In collaboration with the groups of Rainer Hillenbrand (CIC Nanogune Consolider, San Sebastian, Spain) and Erik Bakkers (Philips Research, Eindhoven), we have utilized infrared near-field nanoscopy to probe the free carrier concentration in semiconductor nanowires. With a spatial resolution of 25 nm, we determined the gradient of the free-carrier concentration at the interface between a non-doped and a doped segment and we quantified the free-carrier concentration in the doped region. Controlling the free-carrier concentration and the sharpness of the interface between regions with different doping concentrations allows for fabrication of novel nanowire diodes, transistors or light emitting devices. Please read the article here.

Generic nano-imprint process for fabrication of nanowire arrays.

We have developed a generic process for growing defect-free ordered arrays of nanowire in collaboration with the group of Erik Bakkers from Philips Research. Substrate conformal imprint lithography has been used to pattern gold particle arrays on full 2 inch substrates, that catalyze the growth of the nanowires. From the imprint process, organic residues remain on the surface, which induce the growth of additional undesired nanowires. Cleaning the substrates before growth with a wet chemical etch in combination with a thermal anneal results in uniform nanowire arrays. The cleaning procedure is applicable to other lithographic techniques, and therefore represents a generic process. Please download the article for more information.