Magnetic imaging with nitrogen-vacancy centers in diamond, also known as quantum diamond microscopy, has emerged as a useful technique for the spatial mapping of charge currents in solid-state devices. In this work, we investigate an application to photovoltaic (PV) devices, where the currents are induced by light. We develop a widefield nitrogen-vacancy microscope that allows independent stimulus and measurement of the PV device, and test our system on a range of prototype crystalline silicon PV devices. We first demonstrate micrometer-scale vector magnetic field imaging of custom PV devices illuminated by a focused laser spot, revealing the internal current paths in both short-circuit and open-circuit conditions. We then demonstrate time-resolved imaging of photocurrents in an interdigitated back-contact solar cell, detecting current build-up and subsequent decay near the illumination point with microsecond resolution. This work presents a versatile and accessible analysis platform that may find distinct application in research on emerging PV technologies.
@article{arxiv.2203.12115,
title = {Imaging current paths in silicon photovoltaic devices with a quantum diamond microscope},
author = {S. C. Scholten and G. J. Abrahams and B. C. Johnson and A. J. Healey and I. O. Robertson and D. A. Simpson and A. Stacey and S. Onoda and T. Ohshima and T. C. Kho and J. Ibarra Michel and J. Bullock and L. C. L. Hollenberg and J. -P. Tetienne},
journal= {arXiv preprint arXiv:2203.12115},
year = {2022}
}