Carrier-Resolved Photo-Hall Effect: Unlocking a 140-year-old secret in Hall effect

Abstract

Majority and minority carrier properties such as type, density and mobility represent fundamental yet difficult to access parameters governing semiconductor device performance, most notably solar cells. Obtaining this information simultaneously under light illumination would unlock many critical parameters such as recombination lifetime, recombination coefficient, and diffusion length; while deeply interesting for optoelectronic devices, this goal has remained elusive. We demonstrate here a new carrier-resolved photo-Hall technique that rests on a new equation relating hole-electron mobility difference (Delta mu), Hall coefficient (H), and conductivity (sigma), and a rotating parallel dipole line ac-field Hall system with Fourier/lock-in detection for clean Hall signal measurement [1]. We successfully apply this technique to recent world-record-quality perovskite film and map the results against varying light intensities, demonstrating unprecedented simultaneous access to the above-mentioned parameters.