Structural and Electrical Characterization of Al[sub x]Ga[sub 1−x]N/GaN Interfaces for UV Photodetectors

In the present study, we have investigated the incorporation of 2DEG heterostructures with different Al content (19% and 39%) in UV metal-semiconductor-metal photodetectors (PDs), employing Schottky contacts. The structural properties of the heterostructures on sapphire substrates have been characterized by transmission electron microscopy, high resolution X-ray diffraction, atomic force microscopy, and UV micro-Raman spectroscopy. In order to study the behaviors of the interface phonon modes observed from such 2DEG structures, UV Raman measurements were simultaneously performed with and without applied bias voltages. The electrical properties of the UV PDs have been correlated to the optical observations.