Band-offset effect on localization of carriers and p-type doping of InAs/GaAs core–shell nanowires

• The VBM state of InAs/GaAs core–shell nanowires is mainly localized in InAs-core region.
• The band-offset magnitude of InAs/GaAs core–shell nanowires depends on the sizes of core and shell.
• The highly efficient p-type doping of InAs/GaAs core–shell nanowires is driven by the band-offset effect.

The electronic properties and p-type doping mechanism of InAs/GaAs core–shell nanowires are studied by using the first-principles calculations within density-functional theory. The core–shell structure of nanowires creates one-dimensional band offset at the InAs/GaAs interface. The magnitude of band offset depends on the sizes of core and shell. We find that a highly efficient p-type doping in InAs/GaAs core–shell nanowires can be achieved by introducing the Cd-impurity into the GaAs shell, utilizing the band-offset effect. It is because the valence-band electrons can spontaneously transfer to the Cd-impurity level, resulting in one-dimensional hole gas in the InAs core of nanowires.