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 ∼109 cm−2) have been found to be negatively charged for both n-GaN and Al0.35Ga0.65N/GaN heterostructure samples.