Generation and transport of photoexcited electrons in single-crystal diamond

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 similar to 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 similar to 1.9 eV. These findings shed light on sub-bandgap states in nitrogen-doped single-crystal diamond.