Fig. 2: STEM imaging of dualtronic epitaxial heterostructure.
From: Using both faces of polar semiconductor wafers for functional devices
a, Schematic showing the HEMT-LED heterostructures grown on both faces of a single-crystal c-plane n-GaN substrate. b, HAADF-STEM image showing the GaN/Al0.40Ga0.60N/GaN HEMT. Scale bar, 10 nm. c, Atomic-resolution image corresponding to the uppermost GaN/Al0.40Ga0.60N heterojunction interface that hosts the 2DEG. Scale bar, 2 nm. d, iDPC image in the uppermost GaN layer of the HEMT indicating that the nitrogen polarity follows that of the substrate to the surface. Scale bar, 1 nm. e, HAADF-STEM image showing the LED quantum well, electron blocking layer, cladding and contact layers. Scale bar, 100 nm. f, Atomic-resolution image corresponding to the LED In0.07Ga0.93N/In0.17Ga0.83N/In0.07Ga0.93N single quantum well. Scale bar, 2 nm. g, iDPC image of the p-InGaN contact layers of the LED indicating that the metal polarity follows that of the substrate. Scale bar, 1 nm.
