Graphene/Al 2 O 3 /AlGaN/GaN Schottky MISIM Diode for Sensing Double UV Bands

We propose graphene as a Schottky metal electrode material for an AlGaN/GaN heterostructure layer-based metal–insulator–semiconductor–insulator–metal (MISIM)-type UV sensor. The fabricated AlGaN/GaN MISIM UV sensor showed two distinguishable sensing windows, namely, a UV-A and a UV-B region with sharp cutoff characteristic. The graphene-electrode UV sensor had a lower dark current density and better UV-to-visible rejection ratio than that of a Ni-electrode UV sensor.