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HL: Fachverband Halbleiterphysik

HL 76: Poster IIIC

HL 76.5: Poster

Donnerstag, 19. März 2020, 15:00–17:30, P2/4OG

Light and electron beam induced current analysis of perovskite solar cells — •Felix Müller, Tobias Westphal, and Michael Seibt — University of Göttingen, IV. Physical Institute, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

As perovskite solar cells showing promising properties for future photovoltaics it is of interest to investigate their electronic properties. Light beam induced current (LBIC) or electron beam induced current (EBIC) are well-established techniques to study excess carrier recombination, i.e. to measure their diffusion length and to investigate recombination at extended defects. Both methods locally generate excess charge carriers in a certain generation volume beneath the spot where the beam (electron or light) hits the sample resulting in a short circuit current in a charge-separating junction. A current map is generated by scanning the beam over the sample.

As the spot size of an electron beam is typically smaller than the spot size of a laser, EBIC has a potentially higher spatial resolution. Some perovskites, however, suffer from beam damage produced by high energy electrons inside the SEM which is nearly no problem using LBIC. Despite a reduced spatial resolution of LBIC the excitation energy can be varied by using laser diodes with different wavelengths, to be sensitive to different band gaps.

In our present work we have measured LBIC and EBIC maps of the same perovskite samples to compare them regarding the mentioned properties of both methods. Combining the results of both we achieve a more complete picture of the sample's electronic characteristics.