Scandium aluminum nitride nanowires

Scandium nitride (ScN) and aluminum nitride (AlN) are novel semiconducting materials with tremendous potential for optoelectronic applications. While AlN's bandgap lies in the UV at 6 eV, ScN's bandgap is around 2-2.4 eV. Combinations of these semiconductors can cover most of the visible spectrum (from the UV/violet to up to the color red). This makes the alloying of AlN with ScN an interesting alternative to AlxIn1-xN or InxGa1-xN, the latter of which is currently used for a.o. white light LEDs. The drawback of InN is its poor thermal and chemical stability, whereas ScN is extremely inert and stabile. In this chapter we will introduce the first ever semiconducting Sc x-Al1-xN alloy in the form of nanowires. These nanowires were grown on ScN films, deposited by hydride vapor phase epitaxy on silicon carbide substrates. Though their fabrication was unintentional, we can explain the growth of these ScxAl1-xN nanowires via the formation of nanosized metallic droplets of aluminum on the ScN film. These droplets then acted as catalysts under which the nanowires formed during the final stages of the growth process. The structural properties of these ScxAl1-xN nanowires on ScN films were examined by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive analysis of X-rays (EDX), and X-ray diffraction (XRD). The optical properties were investigated by single nanowire cathodoluminescence (CL)