Suppression of bulk conductivity in InAs/GaSb broken gap composite quantum wells
- Resource Type
- Working Paper
- Authors
- Charpentier, Christophe; Fält, Stefan; Reichl, Christian; Nichele, Fabrizio; Pal, Atindra Nath; Pietsch, Patrick; Ihn, Thomas; Ensslin, Klaus; Wegscheider, Werner
- Source
- Appl. Phys. Lett. 103, 112102 (2013)
- Subject
- Condensed Matter - Mesoscale and Nanoscale Physics
- Language
The two-dimensional topological insulator state in InAs/GaSb quantum wells manifests itself by topologically protected helical edge channel transport relying on an insulating bulk. This work investigates a way of suppressing bulk conductivity by using gallium source materials of different degrees of impurity concentrations. While highest-purity gallium is accompanied by clear conduction through the sample bulk, intentional impurity incorporation lead to a bulk resistance over 1 M\Omega. This resistance was found to be independent of applied magnetic fields. Ultra high electron mobilities for GaAs/AlGaAs structures fabricated in a molecular beam epitaxy system used for the growth of Sb-based samples are reported.