Bending-induced modulation doping: a promising tendency in silicon nanowires

Abstract

Simultaneously achieving high carrier concentration and mobility in silicon nanowires (SiNWs) remains a key challenge in nanoelectronics, largely due to scattering from random dopant distributions. Modulation doping, which spatially separates carriers from dopants, is commonly achieved through complex core–shell heterostructures. Here, using atomistic quantum-mechanical simulations based on the generalized Bloch theorem combined with self-consistent charge density-functional tight-binding (SCC-DFTB), we show that controlled bending enables effective modulation doping in single-crystalline SiNWs. In bending SiNWs, smaller dopants preferentially occupy the compressive side near the NW shell, while carriers are driven to the tensile side near the NW shell by an effective type-I band alignment. Our work suggests that bending is a promising approach for achieving modulation doping in SiNWs without costly heterostructures. The observed spatial separation of carriers from dopants provides indirect evidence for bending-induced modulation doping, while direct verification of charge transfer and carrier transport requires further experimental and theoretical investigation. Nevertheless, this concept offers a potential pathway toward enhanced nanowire-based electronics and optoelectronics.