PhD Defense: Rawa Tanta – University of Copenhagen

PhD Defense: Rawa Tanta

Raman Spectroscopy of InAs based Nanowires & Electronic Characterization of Heterostructure InAs/GaInAs Nanowires

The work presented in this thesis represents two main topics. The first one is mainly about Raman spectroscopy on individual InAs based nanowires. The second part presents electronic characterization of heterostructure InAs/GaInAs nanowires. 

Raman spectroscopy measurements on InAs based nanowires include several topics. Firstly, we use polarized Raman spectroscopy for determining the crystal orientation of the nanowires based on conventional Raman selection rules. We studied the effect of the high power laser irradiation on the nanowire, and its relation to the nanowire surface facets. We present controlled oxidation experiments on InAs nanowires enabled by fabrication of micro-trenches in the substrate and the electronic properties of the oxidized nanowire were also studied. Finally, we present an attempt to detect the LO phonon-plasmon coupled modes.

Finally, we present a study on electrical characterization of InAs/GaInAs heterostructure nanowires. First, we performed selective etching experiments in order to locate the barriers. Second, the barriers were probed electrically by performing thermally activated transport measurements.