Nanoscale EELS analysis of elemental distribution and band-gap properties in AlGaN epitaxial layers

Aluminium gallium nitride (AlGaN) is a strong candidate for high-power and high-temperature electronic devices and short-wavelength (visible and ultraviolet) optoelectronic devices. For band-gap engineering of nitride layers, it is essential to be able to perform an accurate local measurement of their optical properties. In this work, core-loss electron energy loss spectroscopy (EELS), plasmon spectroscopy and valence EELS (VEELS) are compared for the investigation of the local chemistry and band-gap of AlGaN.