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Journal/Book/Conference Title

Applied Physics Letters





DOI of Original Publication



Originally published at

Date of Submission

April 2015


Inversion domains in III-nitride semiconductors degrade the performance of devicesfabricated in them. Consequently, it is imperative that we understand their electrostatic manifestation, the growth conditions under which such domains form, and an effective means of their identification. In what is nominally referred to as Ga-polarity samples, N-polarity domains have a polarization that is reversed with respect to the remainder of the surface, and therefore, have a different potential under strain. We have used surface-potential electric-force microscopy (SP-EFM) to image the electrostaticsurface potential of GaNgrown on sapphire, which is strained due to the thermal mismatch between the substrate and GaN. Employing a control sample with side-by-side Ga- and N-polarity regions, we have established the EFM mode necessary to identify inversion domains on GaN samples grown by molecular-beam epitaxy. This method is not sensitive to topology and has a spatial resolution of under 100 nm. The measured surface potentials for Ga-face and N-face regions are +25±10 and −30±10 mV, respectively, with respect to the sapphire substrate, where the sign is consistent with Ga- and N-polarity GaN under compressive strain due to thermal mismatch with the sapphire substrate.


Jones, K.M., Visconti, P., Yun, F., et al. Investigation of inversion domains in GaN by electric-force microscopy. Applied Physics Letters, 78, 2497 (2001). Copyright © 2001 AIP Publishing LLC.

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