Carrier-Resolved Photo Hall Measurement in World-Record-Quality Perovskite and Kesterite Solar Absorbers

TL;DR

This paper introduces a novel carrier-resolved photo-Hall measurement technique that enables simultaneous determination of fundamental carrier properties in high-quality perovskite and kesterite solar absorbers under illumination.

Contribution

The authors develop a new identity and measurement system for directly accessing carrier type, density, and mobility simultaneously in illuminated semiconductors, advancing characterization capabilities.

Findings

Successfully applied to record-quality perovskite and kesterite films

Mapped carrier properties against varying light intensities

Achieved unprecedented simultaneous access to multiple carrier parameters

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 identity relating hole-electron mobility difference ($\Delta\mu$), Hall coefficient ($h$), and conductivity ($\sigma$): $\Delta\mu=(2+d\ln h/d\ln \sigma)\,h\,\sigma$, and a rotating parallel dipole line ac-field Hall system with Fourier/lock-in detection for clean Hall signal measurement. We successfully apply this technique to recent world-record-quality perovskite and kesterite films and map the results against varying light intensities, demonstrating unprecedented simultaneous access to the above-mentioned parameters.