DNA chains can be broken by UV radiation at a wavelength of about 260 nm, which makes LEDs in this range potentially useful for applications such as biological sensors, water and air sterilization, fridge sanitization etc...



Unfortunately, the realization of efficient UV LEDs is presently hindered by the bad structural and optical properties of AlGaN bidimensionnal layers. By contrast, the absence of structural defects in nanowires is expected to result in a qualitative break-down, eventually permitting to realize efficient UV LEDs in the wavelength of interest.



Due to their specific geometry, nanowires are free of the structural defects usually plaguing bidimensionnal layers of nitride materials. As a matter of fact, such bidimensionnla layers usually exhibit high densities of dislocations (typically 10^7 to 10^10/cm2) while nanowires are completely free of dislocations.



These outstanding structural properties of GaN and AlGaN nanowires make them particularly attractive for ultimate optical spectroscopy studies as well as for the realization of innovative UV LEDs.



The goal of the PhD project will be to study the growth, the structural and optical properties of AlxGa1-xN/ AlyGa1-yN nanowire heterostructures. The student will integrate a group internationnally recognized for its expertise in the field of III-N semiconductor physics. The laboratory is mostly interested in basic research issues but is also maintaining an active collaboration with partners in applied science.