Generation and transport of photoexcited electrons in single-crystal diamond

TL;DR

This study investigates the behavior of photoexcited electrons in nitrogen-rich single-crystal diamond, revealing long-lived trapping dynamics, electron conduction confirmation, and sub-bandgap state insights through time-resolved measurements.

Contribution

It provides new experimental evidence on charge trapping, conduction, and sub-bandgap states in nitrogen-doped diamond using time-dependent photocurrent and Hall effect measurements.

Findings

Charge carriers are confirmed to be electrons.

Long charge storage lifetimes of about 3 hours.

Photoconduction turns on at approximately 1.9 eV.

Abstract

We report time-dependent photocurrent and transport measurements of sub-bandgap photoexcited carriers in nitrogen-rich (type Ib), single-crystal diamond. Transient carrier dynamics are characteristic of trapping conduction with long charge storage lifetimes of ~3 hours. By measuring the photoexcited Hall effect we confirm that the charge carriers are electrons and by varying the excitation energy we observe a strong turn-on in the photoconduction at ~1.9 eV. These findings shed new light on sub-bandgap states in nitrogen doped single-crystal diamond.