Smart, enhanced detection of ultraviolet (UV) radiation will be a key enabling technology for many forthcoming technological revolutions in fields such as industrial processing, space research, defence and medicine. AlGaN alloys
with high Al content are the perfect materials for this type of device. By varying their composition, the absorption edge can be precisely controlled across the whole UV range down to wavelengths as short as 200 nm. AlGaN-based
photodetectors are fast, with very low dark currents, highly biocompatible, and chemically stable. However, two main problems limit their development: the difficulty in achieving satisfactory p-type doping, and the presence of
polarization fields that disrupt the internal electric field and make it difficult the separation of the photo-generated carriers. This project aims to use N-polar AlGaN materials to tackle both problems. This material orientation has proved to favour incorporation of p-type impurities and induce higher electric fields for carrier separation.