Barbara Szafranski

1 Introduction Labeling organic molecules or biological structures with luminescent nanoparticles facilitates the analysis of molecular and cellular processes through optical imaging techniques [1].

1 Introduction In the last few decades, the development of ultraviolet (UV) light-emitting diodes (LEDs) has been strongly driven forward by the wide range of applications such as water purification, phototherapy, and sterilization.[1] For the fabrication of AlGaN-based LEDs in the UV range, a high-quality AlN buffer layer on a sapphire substrate is presently viewed as a prerequisite for high quantum efficiency.