We demonstrate the application of two-photon absorption transient current
technique to wide bandgap semiconductors. We utilize it to probe charge
transport properties of single-crystal Chemical Vapor Deposition (scCVD)
diamond. The charge carriers, inside the scCVD diamond sample, are excited by a
femtosecond laser through simultaneous absorption of two photons. Due to the
nature of two-photon absorption, the generation of charge carriers is confined
in space (3-D) around the focal point of the laser. Such localized charge
injection allows to probe the charge transport properties of the semiconductor
bulk with a fine-grained 3-D resolution. Exploiting spatial confinement of the
generated charge, the electrical field of the diamond bulk was mapped at
different depths and compared to an X-ray diffraction topograph of the sample.
Measurements utilizing this method provide a unique way of exploring spatial
variations of charge transport properties in transparent wide-bandgap
semiconductors.Comment: This article may be downloaded for personal use only. Any other use
requires prior permission of the author and AIP Publishing. The following
article appeared in Applied Physics Letters and may be found at
https://doi.org/10.1063/1.509085