Correlated scanning Kelvin probe and conductive atomic force microscopy studies of dislocations in gallium nitride
- 1 August 2003
- journal article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 94 (3) , 1448-1453
- https://doi.org/10.1063/1.1586952
Abstract
Scanning Kelvin probe microscopy (SKPM) and conductive atomic force microscopy (C-AFM) have been used to image surfaces of GaN grown by molecular beam epitaxy. Detailed analysis of the same area using both techniques allowed imaging and comparison of both surface potential variations arising from the presence of negatively charged threading dislocations and localized current leakage paths associated with dislocations. Correlations between the charge state of dislocations, conductivity of current leakage paths, and dislocation type were thereby established. Analysis of correlated SKPM and C-AFM images revealed a density of negatively charged features of ∼3×108 cm−2 and a localized current leakage path density of ∼3×107 cm−2, with approximately 25% of the leakage paths spatially correlated with negatively charged dislocation features. Based on correlated topography and previous studies quantifying the densities of edge, screw, and mixed dislocations, our results suggested that dislocations having an edge component behave as though negatively charged while pure screw dislocations are solely responsible for the observed leakage paths and are uncharged.This publication has 23 references indexed in Scilit:
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