Crystallographic Polarity Measurements in Two-Terminal GaN Nanowire Devices by Lateral Piezoresponse Force Microscopy

Published

July 23, 2020

Author(s)

Matthew Brubaker, Alexana Roshko, Samuel Berweger, Paul T. Blanchard, Todd E. Harvey, Norman A. Sanford, Kristine Bertness

Abstract

Lateral piezoresponse force microscopy (L-PFM) is demonstrated as a reliable method for determining the crystallographic polarity of individual, dispersed GaN nanowires that were functional components in electrical test structures. In contrast to PFM measurements of vertically oriented (as-grown) nanowires, where a biased probe tip couples to out-of-plane deformations through the d33 piezoelectic coefficient, the L-PFM measurements in this study were implemented on horizontally oriented nanowires that coupled to shear deformations through the d15 coefficient. L-PFM phase-polarity relationships were determined experimentally using a bulk m-plane GaN sample with a known [0001] direction and further indicated that the sign of the d15 piezoelectric coefficient was negative. L-PFM phase images successfully revealed the in-plane [0001] orientation of self-assembed GaN nanowires as part of a growth polarity study and results were validated against scanning transmission electron microscopy lattice images. Combined characterization of electrical properties and crystallographic polarity was also implemented for two-terminal GaN/Al0.1Ga0.9N/GaN nanowires devices, demonstrating L-PFM measurements as a viable tool for assessing correlations between device rectification and polarization-induced band bending.

Citation

Nanotechnology

Pub Type

Journals

Download Paper

https://doi.org/10.1088/1361-6528/ab9fb2

Local Download

Keywords

Nanowires, GaN, Crystallographic Polarity, Piezoresponse Force Microscopy

Citation

Brubaker, M. , Roshko, A. , Berweger, S. , Blanchard, P. , Harvey, T. , Sanford, N. and Bertness, K. (2020), Crystallographic Polarity Measurements in Two-Terminal GaN Nanowire Devices by Lateral Piezoresponse Force Microscopy, Nanotechnology, [online], https://doi.org/10.1088/1361-6528/ab9fb2, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920127 (Accessed November 26, 2025)