Sub-Picosecond Carrier Dynamics Explored using Automated High-Throughput Studies of Doping Inhomogeneity within a Bayesian Framework

TL;DR

This study employs automated high-throughput photoluminescence spectroscopy combined with Bayesian analysis to investigate sub-picosecond hot-carrier dynamics and doping inhomogeneity in over 20,000 Zn-doped GaAs nanowires, revealing correlations and electronic behaviors.

Contribution

It introduces a Bayesian framework for analyzing large-scale spectroscopic data to uncover inhomogeneity and ultrafast dynamics in nanomaterials.

Findings

Revealed doping and diameter correlation in nanowires.

Identified hot-carrier recombination as key to photoluminescence lineshape.

Demonstrated sub-picosecond electronic dynamics using lifetime variation.

Abstract

Bottom-up production of semiconductor nanomaterials is often accompanied by inhomogeneity resulting in a spread in electronic properties which may be influenced by the nanoparticle geometry, crystal quality, stoichiometry or doping. Using photoluminescence spectroscopy of a population of more than 20,000 individual Zn-doped GaAs nanowires, we reveal inhomogeneity in, and correlation between doping and nanowire diameter by use of a Bayesian statistical approach. Recombination of hot-carriers is shown to be responsible for the photoluminescence lineshape; by exploiting lifetime variation across the population, we reveal hot-carrier dynamics at the sub-picosecond timescale showing interband electronic dynamics. High-throughput spectroscopy together with a Bayesian approach are shown to provide unique insight in an inhomogeneous nanomaterial population, and can reveal electronic dynamics otherwise requiring complex pump-probe experiments in highly non-equilibrium conditions.