Quantitative relevance of substitutional impurities to carrier dynamics in diamond

TL;DR

This study quantifies how substitutional impurities like boron and nitrogen affect carrier dynamics in synthetic diamond, providing key parameters for understanding and improving diamond-based electronic materials.

Contribution

It presents precise measurements of impurity concentrations and capture cross sections, advancing the understanding of impurity-related carrier trapping in diamond.

Findings

Determined electron capture cross section for boron: 1.3x10^-14 cm^2

Determined exciton capture cross section for nitrogen: 3.1x10^-14 cm^2

Mobility trends explained by impurity and exciton scattering

Abstract

We have quantified substitutional impurity concentrations in synthetic diamond crystals down to sub parts-per-billion levels. The capture lifetimes of electrons and excitons injected by photoexcitation were compared for several samples with different impurity concentrations. Based on the assessed impurity concentrations, we have determined the capture cross section of electrons to boron impurity, sA=1.3x10^-14 cm2, and that of excitons to nitrogen impurity, sD^ex=3.1x10^-14 cm2. The general tendency of the mobility values for different carrier species is successfully reproduced by including carrier scattering by impurities and by excitons.