Polarity control in wide band gap semiconductors like GaN and ZnO is essential for their integration into a large number of electronic and optoelectronic devices . Following the demonstration in Vincent Consonni's team that ZnO nanowires grown by chemical bath deposition can be of either oxygen or zinc polarity , we have conducted several investigations aiming at elucidating the effects of the polarity on their growth mechanisms and on their properties.
We have shown the polarity transfer from a polycrystalline ZnO seed layer into ZnO nanowires by anomalous x-ray diffraction in synchrotron, favouring a statistical analysis over 10 million of nano-objects .
We have also revealed that Zn-polar ZnO nanowires elongate with a larger growth rate than O-polar ZnO nanowires. A theoretical modelling of the growth process has allowed us to attribute that difference to a larger surface reaction rate constant in the case of Zn-polar ZnO nanowires than in the case of O-polar ZnO nanowires .
These ongoing investigations with strong fundamental and applicative interests are specifically conducted in the framework of the project ANR ROLLER (2018 – 2021) that is in collaboration with Institut Néel, Institut des Nanotechnologies de Lyon, and LGEF.