Probing metastable space-charge potentials in a wide bandgap semiconductor

TL;DR

This paper investigates metastable space-charge potentials in wide bandgap semiconductors, using color centers in diamond to inject and probe carriers, revealing complex charge patterns and guiding effects beyond steady-state models.

Contribution

It introduces a novel approach to study and manipulate metastable space-charge patterns in wide bandgap semiconductors using optical and electrical control.

Findings

Formation of metastable charge patterns in diamond

Control of charge pattern shape via injection timing

Demonstration of space-charge-induced carrier guiding

Abstract

While the study of space charge potentials has a long history, present models are largely based on the notion of steady state equilibrium, ill-suited to describe wide bandgap semiconductors with moderate to low concentrations of defects. Here we build on color centers in diamond both to locally inject carriers into the crystal and probe their evolution as they propagate in the presence of external and internal potentials. We witness the formation of metastable charge patterns whose shape - and concomitant field - can be engineered through the timing of carrier injection and applied voltages. With the help of previously crafted charge patterns, we unveil a rich interplay between local and extended sources of space charge field, which we then exploit to show space-charge-induced carrier guiding.