Fig. 1: Single crystalline ferroelectric ScAlN/GaN heterostructure.
From: Unveiling interfacial dead layer in wurtzite ferroelectrics
a Schematic of the MBE-grown ScAlN/GaN heterostructure, along with the electrical configuration used for ferroelectric measurements. b Cross-sectional HAADF-STEM image of the ScAlN/GaN heterostructure. Insets show corresponding EDS elemental maps for Ga, Sc, and Al, respectively. c Atomic-resolution HAADF-STEM image (left) and ABF-STEM image (bottom right) of the ScAlN/GaN interface growing along the [0001] direction. The inset (top right) displays the atomic model for [0001]-orientated wurtzite M-polar III-nitride lattice. Metal (M, yellow) and nitrogen (N, light blue) atoms are embedded in the ABF-STEM image to highlight the inherited M-polar lattice of ScAlN from underlying GaN. d P-E and corresponding J-E hysteresis loops, recorded at 1 kHz, from a typical ScAlN capacitor shown in (a) confirming ferroelectricity.
