Atomic Resolved EELS color map of GaAs/Ga2O3
Paolo Longo, Ph.D., Gatan, Inc. Sample courtesy of University of Glasgow Microscope courtesy of Dr. Yan Xin at Florida State University, Tallahassee, FL Acknowledgement to Dr. Toshiro Aoki at Jeol USA (now at ASU) for helping set up microscope for experiment.

Atomic Resolved EELS color map of GaAs/Ga2O3

Dumbbell structure of GaAs on left hand side of color map is clearly resolved, and Ga and As atomic columns are visible. Interface region shows presence of Ga2O monolayer responsible for keeping Fermi level unpinned, which allows the electronic device to be turned on or off.

Methods

Probe-corrected JEOL ARM 200 TEM/STEM microscope; C-FEG emission gun; GIF Quantum® ES system; Ga L at 1115 eV (green), As L at 1323 eV (red) and O K at 532 eV (blue); voltage: 200 kV; STEM mode; EELS spectrum (300 – 2300 eV) exposure time: 10 ms; dataset size: 90 x 30 pixels; total exposure time: 36 s