Optimized Electro-PyroElectric configurations for thermal and electrical characterization: Exploring Cr-Doped GaAs for thermoelectric applications

• Sequential FEPE–IEPE configurations enables unified, nondestructive thermal–electrical characterization of semiconductors. • Configuration-specific fitting consistently extracts thermal and electrical parameters. • Cr doping enhances electrical conductivity, yet fails to overcome GaAs's high κ limitation. • Cr-doped GaAs shows high Seebeck coefficient but limited zT due to high lattice κ. • FEPE–IEPE platform is generalizable across diverse thermoelectric material systems. Accurate and coherent evaluation of thermal and electrical transport parameters is essential for optimizing thermoelectric (TE) materials. In this work, optimized Electro-PyroElectric (EPE) complementary configurations are implemented sequentially to characterize Cr-doped GaAs and assess its thermoelectric potential. The EPE method enables nondestructive, frequency-resolved measurements of thermal diffusivity, thermal conductivity, and electrical transport within a unified framework. By sequentially employing the complementary Front (FEPE) and Inverse (IEPE) configurations, experimental amplitude and phase spectra are fitted to configuration-specific multilayer analytical models to extract the relevant transport parameters and then evaluate the Seebeck coefficient. Cr-doped GaAs sample exhibits a thermal conductivity of 52 W m -1 K -1 , a thermal diffusivity of 3.3 10 -5 m 2 s -1 , and a DC conductivity of 17.8 S m -1 . The Seebeck coefficient, evaluated using non-degenerate semiconductor transport theory, reaches -496 μV K -1 . Although Cr incorporation improves electrical transport, the intrinsically high lattice thermal conductivity of GaAs significantly limits the power factor, resulting in a low thermoelectric figure of merit (zT). Theoretical transport calculations indicate an optimal donor concentration near 2.5 10 18 cm -3 , yet the corresponding predicted zT remains far below that of state-of-the-art thermoelectrics such as Bi 2 Te 3 . These results highlight the effectiveness of optimized EPE configurations for simultaneous thermal–electrical characterization, while also revealing the fundamental limitations of Cr-doped GaAs for thermoelectric applications. The sequential FEPE–IEPE approach presented here offers a generalizable, versatile, non-destructive platform applicable to a wide range of emerging thermoelectric systems, including low-thermal-conductivity chalcogenides and flexible organic layers, within a single experimental framework.