First - Principles investigation of electronic structures and thermoelectric properties of GaX (X = N, P, Sb, As)...

The thermoelectric properties of four materials, GaN, GaP, GaSb, and GaAs, were systematically reviewed and analyzed at different temperatures (300-900 K) using density functional theory and Boltzmann transport theory. It was found that gallium phosphide and GaSb exhibit excellent thermal stability. GaN exhibits significant advantages in the p-type region, demonstrating superior Seebeck coefficient (2810 μV/K), electrical conductivity (1.12 × 10²⁰ 1/Ωms), and κ_e (4.0 × 10¹⁴W/m·K) opposed to the other materials. In the n-type region, GaP shows a higher Seebeck coefficient (3060 μV/K) and electrical conductivity (1.39 × 10²⁰ 1/Ωms), along with a lower κ_e (0.6 × 10¹⁴W/m·K). The thermoelectric performance of GaSb and GaAs is limited by their moderate Seebeck coefficients and relatively high thermal conductivities. Overall, P-type GaN achieves the highest power factor at elevated temperatures (3.8 × 10¹¹W/mK²s), as its band structure effectively balances the Seebeck coefficient and electrical conductivity. Meanwhile, GaP attains a ZT_e of 0.979 in the n-type region, owing to its excellent Seebeck coefficient and reduced thermal conductivity.This study elucidates the correlation between the thermoelectric properties of III-V semiconductor materials and their energy band structures, carrier transport mechanisms, and phonon scattering, serving as a theoretical foundation for the rational design of high-performance thermoelectric materials.