"Semiconductor nanowires: from LEDs to solar cells"
Relatore: Prof. Silvija Gradecak
Sala A, IMEM - CNR
28 Giugno 2012 ore 15.00
|Semiconductor nanowires are quasi-one-dimensional single-crystals that have emerged as
promising materials for the development of photonic and electronic devices with enhanced
performance. Nanowires offer solutions to some of the current challenges in science and
engineering, but realization of their full potential will be ultimately dictated by the ability to control
their structure, composition, and size with high accuracy. In this talk, I will discuss our recent
results on the controlled growth, doping, and applications of III-V nanowires, as well as advanced
electron microscopy techniques for direct correlation of structural and physical properties with high
spatial resolution. We have developed a simple, yet powerful, approach to modulate both the
diameter and composition of individual III-V nitride nanowires by adjusting in-situ the nanowire
seed particle composition and volume. By elucidating the underlying mechanisms controlling
structural evolution, we demonstrated the synthesis of axial InN/InGaN nanowire heterojunctions,
compositionally tunable AlGaAs nanowires, GaAs/AlGaAs core-shell nanowires, and their
controlled doping. We have demonstrated that the cathodoluminescence (CL) technique, coupled
with scanning transmission electron microscopy (STEM), effectively bypasses the resolution limit
of conventional far-field photoluminescence spectroscopy and allows direct structure-property
correlation on the nanoscale. The CL-STEM optical studies of single nanowire heterostructures
with spatial resolution of <20 nm will be discussed. Finally, applications of semiconductor
nanowires for LED and solar cell applications will be described.
La Prof.essa Gradecak è stata insignita del premio Nano Letters Young Investigator Lectureship per il 2012, per il
contributo scientifico di grande impatto nel campo della nanoscienza e nanotecnologia.