Microscopic analysis of semi- and non-polar nitrides: surfaces, interfaces, and defects

In project P6, dislocations, fluctuations, and piezoelectric fields as dominant effects in InGaN quantum well light emitters are investigated by transmission electron microscopy and optical microscopic spectroscopy. For the electron microscopic investigations it is planned to do both supportive structural investigations of cross-sectionally prepared specimens in order to monitor various aspects of the growth process (density and type of dislocations, interfacial properties, compositional analysis in quantum wells) and to detect and measure quantitatively the electrostatic (piezoelectric) fields which exist at the interfaces of quantum well structures and cause the quantum confined stark effect which leads to a deterioration of quantum efficiency.  With micro-photo­luminescence we address the influence of growth orientation and of dislocations on strain, piezoelectric field, light polarization, and internal quantum efficiency to determine fundamental optoelectronic properties of semi- and non-polar light emitters. The spatial resolution of micro-photoluminescence and an applied bias field provide a crucial additional parameter space to measure local properties, quantum well fluctuations, and the internal field.

Project Leader


  • Josef Zweck
  • Institute of Experimental and Applied Physics
  • University of Regensburg
  • 93040 Regensburg
  • Tel.: +49 (0)941/943-2590
  • Fax: +49 (0)941/943-4544