Nonlocal Si δ-doping in horizontally-aligned GaAs nanowires
Article
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
Achieving quasi-ideal one-dimensional electronic transport in semiconductor nanowires (NWs) requires nonlocal doping to reduce carrier scattering from ionized dopants. A common technique in quantum wells is heavy doping of an atomic monolayer, known as a δ-doping layer, positioned just outside the active region. Given the structural similarities between quantum wells and self-assembled NWs on high-index substrates by Molecular Beam Epitaxy, exploring δ-doping as a solution to enable dopant incorporation while minimizing defects is compelling. Due to limited studies on δ-doping in high-index orientations, this work presents a numerical analysis that self-consistently solves the Poisson and Schrödinger equations to establish the positioning and doping levels of a double δ-layer within the AlGaAs barriers of GaAs NWs. By considering Si diffusion lengths and critical scattering distances, the aim is to minimize carrier spillover into the active region, providing practical guidance for fabricating such structures. Samples grown under these conditions were analyzed using Reflection High-Energy Electron Diffraction, Atomic Force Microscopy, photoreflectance (PR), and photoluminescence. PR measurements provided key insight into the internal electric fields, revealing a slight discrepancy attributed to Si segregation during growth, which allowed us to estimate a segregation of approximately 1 nm. This analysis further underscores the utility of PR as a non-destructive technique for probing doping and segregation effects. Importantly, the δ-layers do not hinder NW formation, making them a valuable strategy for incorporating high doping levels in NWs suitable for practical applications.
