Nanopipes in GaN: photo-etching and TEM study

¹ National Center for HREM, Kavli Institute of Nanoscience Delft University of Technology, Rotterdamseweg 137, 2628 AL Delft, The Netherlands
² Experimental Solid State Physics III, RIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
³ High Pressure Research Center, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland

Corresponding author: S.Lazar@tnw.tudelft.nl

Received: 19 June 2003
Accepted: 28 January 2004
Published online: 15 July 2004

Abstract

Photochemical (PEC) etching and transmission electron microscopy (TEM) have been used to study the defects in hetero-epitaxial GaN layers. TEM proved that PEC etching reveals not only dislocations but also nanopipes in the form of protruding, whisker-like etch features. It is shown by diffraction contrast techniques that the nanopipes are screw coreless dislocations. An example is shown of the transformation of a normal full-core screw dislocation into a nanopipe. The PEC/TEM experiments indicate the presence of electrically active (recombinative) species in the vicinity of the nanopipes.