Ultrafast Dynamics of the Topological Semimetal GdSb x Te 2–x–δ in the Presence and Absence of a Charge Density Wave

Kirby, Robert J.; Montanaro, Angela; Giusti, Francesca; Koch-Liston, André; Lei, Shiming; Petrides, Ioannis; Narang, Prineha; Burch, Kenneth S.; Fausti, Daniele; Scholes, Gregory D.; Schoop, Leslie M.

doi:10.1021/acs.jpcc.2c06120

Secondary‐ion mass spectrometry (SIMS) is used to determine impurity concentrations of carbon and oxygen in two scandium‐containing nitride semiconductor multilayer heterostructures: Sc_xGa_1−xN/GaN and Sc_xAl_1−xN/AlN grown by molecular beam epitaxy (MBE). In the Sc_xGa_1−xN/GaN heterostructure grown in metal‐rich conditions on GaN–SiC template substrates with Sc contents up to 28 at%, the oxygen concentration is found to be below 1 × 10¹⁹ cm⁻³, with an increase directly correlated with the scandium content. In the Sc_xAl_1−xN–AlN heterostructure grown in nitrogen‐rich conditions on AlN–Al₂O₃template substrates with Sc contents up to 26 at%, the oxygen concentration is found to be between 10¹⁹and 10²¹ cm⁻³, again directly correlated with the Sc content. The increase in oxygen and carbon takes place during the deposition of scandium‐alloyed layers.

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