Scanning Kelvin probe microscopy characterization of dislocations in III-nitrides grown by metalorganic chemical vapor deposition

Scanning Kelvin probe microscopy has been used in conjunction with noncontact atomic force microscopy for characterizing dislocations in n-GaN and Al0.35Ga0.65N/GaN heterostructures. The surface potential variations around the dislocations present in the Al0.35Ga0.65N/GaN heterostructure have been observed to be 0.1-0.2 V with full width at half maximums (FWHMs) of 100-200 nm. On the other hand, n-GaN shows potential variations of 0.3-0.5 V having FWHMs of 20-50 nm. The dislocations (present in densities of similar to 10(9) cm(-2)) have been found to be negatively charged for both n-GaN and Al0.35Ga0.65N/GaN heterostructure samples. (C) 2001 American Institute of Physics.