Combined Atomic Force Microscopy and Scanning Tunneling Microscopy Imaging of Cross-Sectioned GaN Light-Emitting Diodes

J. W. Bender, M. E. Salmon, P. E. Russell

North Carolina State University, Analytical Instrumentation Facility, Raleigh, North Carolina, USA

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Summary: Cross-sectional scanning tunneling microscopy (STM) was combined with atomic force microscopy (AFM) over the same area to characterize a cross-sectioned GaN light emitting diode. Because GaN is typically grown on a non-native substrate and also forms a wurtzite crystal structure, a cryogenic cleaving technique was developed to generate smooth surfaces. The depletion region surrounding the p-n junction was clearly identified using STM. Furthermore, by imaging under multiple sample biases, distinctions between the n-doped and p-doped GaN could be made.

Key words: Key words: gallium nitride, scanning tunneling microscopy, atomic force microscopy, cross-section, light emitting diode

PACS: 61.16.Ch, 07.79.-v, 07.79.Lh, 07.79.Cz

This project was supported by the Research and Development Unit, DID, of Universidad Austral de Chile, Project S-98-03.