Optical microcharacterization of complex GaN heterostructures

摘要

Almost all modern semiconductor micro-and nanao-structures consist of two or more different materials, sometimes ternary or quaternary allys, separated by hetero-interfaces which strongly influence all physical properties and processes in these structures. COmmon to all these semiconductor micro-and nano-heterostructures is their strong s patial inhomogentiy. They intentionally and/or unintentionally consist of various microscopic regions or domains of different chemical composition and energy band structure. For a detailed understanding a systematic determination and a correlation of the structural, chemical, electronic, and optical properties of these complex semiconductor hetero-structures on a micro-or nano-scale is essential. Luminescence techniques belong to the most sensitive, non-destructive methods of analyzing both intrinsic and extrinsic semiconductor properties. Combining the luminescence spectroscopy with the high spatial resolution of a scanning electron microscope (SEM), realized by the technique of cathodoluminescence (CL) microscopy, provides a powerful tool for the nano-characterization of semiconductors, their hetero-structures as well as their interfaces.