In this work, the structural and electrical properties of a GaN-based p-n heterostructure are studied using cross-sectional Atomic Force Microscopy, Friction Force Microscopy, Electrical Force Gradient Microscopy, and Surface Potential Microscopy. Using Atomic Force Microscopy and Friction Force Microscopy, we were able to identify and measure the thickness of the layers present in the heterostructures. The electrical conductivity type of the different layers as well as the p-n junction, and piezoelectric fields were identified and studied using Electric Force Gradient Microscopy and Surface Potential Microscopy. © 2003 Elsevier Science Ltd. All rights reserved.3405/08/15571573Martin, Y., Abraham, D.W., Wickramasinghe, K., High-resolution capacitance measurement and potentiometry by force microscopy (1988) Appl. Phys. Lett., 52 (13), pp. 1103-1106Nonnenmacher, M., O'Boyler, M.P., Wickramasinghe, H.K., Kelvin probe force microscopy (1991) Appl. Phys. Lett., 58 (25), pp. 2921-2924Henning, A.K., Hochwitz, T., Scanning probe microscopy for 2-D semiconductor dopant profiling and device failure analysis (1996) Mater. Sci. Engng, B, 42 (1-3), pp. 88-98Tanimoto, J.M., Vatel, O., Kelvin probe force microscopy for characterization of semiconductor devices and processes (1996) J. Vac. Sci. Technol., B, 14 (2), pp. 1547-1551Robin, F., Jacobs, H., Homan, O., Stemmer, A., Bachtold, W., Investigation of the cleaved surface of a p-i-n laser using Kelvin probe force microscopy and two-dimensional physical simulations (2000) Appl. Phys. Lett., 76 (20), pp. 2907-2909Ballif, C., Moutinho, H.R., Al-Jassim, M.M., Cross-sectional electrostatic force microscopy of thin-film solar cells (2001) J. Appl. Phys., 89 (2), pp. 1418-1424Koley, G., Spencer, M.G., Surface potential measurements on GaN and AlGaN/GaN heterostructures by Kelvin probe microscopy (2001) J. Appl. Phys., 90 (1), pp. 337-344