Decoration effects as origin of dislocation-related charges in gallium nitride layers investigated by scanning surface potential microscopy

The electrical charge state of threading dislocations in differently doped GaN is investigated by scanning surface potential microscopy in conjunction with tapping mode atomic force microscopy. The dislocations are found to be either negatively charged or neutral depending on the type of doping atoms in the layers, i.e., Mg acceptors, Si donors, or without intentional doping. The results are interpreted in terms of decoration of the dislocations with other defects resulting in a partial compensation of the core charge by the accumulated charges around.

[1]  F. Ponce,et al.  Determination by Electron Holography of the Electronic Charge Distribution at Threading Dislocations in Epitaxial GaN , 2002 .

[2]  Richard J. Molnar,et al.  Effect of growth stoichiometry on the electrical activity of screw dislocations in GaN films grown by molecular-beam epitaxy , 2001 .

[3]  O. Ambacher,et al.  Carrier Recombination at Screw Dislocations in n‐Type AlGaN Layers , 1999 .

[4]  Tetsuya Suemitsu,et al.  Correlation between current–voltage characteristics and dislocations for n-GaN Schottky contacts , 2001 .

[5]  E. C. Carr,et al.  CORRELATION OF CATHODOLUMINESCENCE INHOMOGENEITY WITH MICROSTRUCTURAL DEFECTS IN EPITAXIAL GAN GROWN BY METALORGANIC CHEMICAL-VAPOR DEPOSITION , 1997 .

[6]  James S. Speck,et al.  Dislocation mediated surface morphology of GaN , 1999 .

[7]  B. Beaumont,et al.  Luminescence of epitaxial GaN laterally overgrown on (0001) sapphire substrate: Spectroscopic characterization and dislocation contrasts , 2001 .

[8]  Shuji Nakamura,et al.  Time-resolved photoluminescence spectroscopy in GaN-based semiconductors with micron spatial resolution , 2000 .

[9]  D. Cherns,et al.  Electron holography studies of the charge on dislocations in GaN. , 2002, Physical review letters.

[10]  Michael G. Spencer,et al.  Scanning Kelvin probe microscopy characterization of dislocations in III-nitrides grown by metalorganic chemical vapor deposition , 2001 .

[11]  James S. Speck,et al.  Scanning capacitance microscopy imaging of threading dislocations in GaN films grown on (0001) sapphire by metalorganic chemical vapor deposition , 1998 .

[12]  N. Browning,et al.  Intrinsic electronic structure of threading dislocations in GaN , 2002 .

[13]  Fernando Ponce,et al.  Characterization of dislocations in GaN by transmission electron diffraction and microscopy techniques , 1996 .

[14]  A. Dadgar,et al.  Electrical microcharacterization of dislocation-related charges in GaN-based single layers by scanning probe microscopy techniques , 2003 .

[15]  F. Ponce,et al.  Electron holography studies of the charge on dislocations in GaN. , 2001, Physical review letters.

[16]  F. Frank.  Capillary equilibria of dislocated crystals , 1951 .