Nanomaterials @ Interfaces Research Group

Gamma tin monoselenide (γ-SnSe) thin films were deposited from solution on GaAs(100) substrates while systematically varying the reaction temperature (0–10 °C) to elucidate the relationship between growth temperature, microstructure, and charge transport behavior. X-ray diffraction confirmed phase-pure γ-SnSe across all deposition temperatures, whereas Raman spectroscopy revealed the emergence of α-SnSe signatures at 10 °C, consistent with HRSEM observations of flake-like grains indicative of mixed phase growth. Williamson–Hall analysis showed the largest crystallite size at 5 °C, while strain values remained negligible (<0.5%) for all samples. Temperature-dependent electrical measurements showed room-temperature conductivity varying by more than an order of magnitude across the series, peaking at 5 °C. For films deposited between 0 °C and 7 °C, the mobility in the intrinsic regime follows a power law dependence μ∝T^-α with α ≈ 1.5, consistent with thermally activated phonon scattering as the dominant mechanism, while the mobility magnitude correlates with crystallite size. In contrast, the 10 °C film exhibits mixed phase–induced barrier-limited transport with an activation energy of ∼ 23 meV. Kelvin probe force microscopy show small work function variations within ± 0.05 eV across all samples. These findings establish a direct synthesis–structure–property relationship in γ-SnSe and identify 5 °C as an optimal deposition temperature for achieving enhanced microstructural quality and electronic performance.