Charge Carrier Separation in Modulation Doped Coaxial Semiconductor Nanowires

Complementary doped donor and acceptor dipoles effectively generate confinement potentials for carriers across a p-type/intrinsic/n-type coaxial nanowire due to the lineup of charge neutrality level. In order to verify this physical picture, we employ first-principles density functional theory to study the confinement of electrons and holes in complementary boron (p-type) and phosphorus (n-type) doped coaxial silicon nanowires. An analysis of the charge density distributions reveals that the electrons and holes are spatially separated in core and outer shell regions, respectively, in conformity with a type-II lineup of band structures.