Correlation between nanoflower morphology and temperature-dependent charge transport in IrSb₃ thin-film transistors

Skutterudite materials have been extensively studied for thermoelectric energy conversion; however, their potential in device-integrated semiconductor electronics remains largely unexplored. Here, we establish a comprehensive correlation among thin-film structure, transport properties, and device functionality in molarity-controlled IrSb₃ nanostructured films employed as active channels in thin-film transistors (TFTs). Increasing precursor concentration (0.25–5 mM) induces a transition from discontinuous granular films to interconnected nanoflower architectures, accompanied by improved crystallinity and carrier percolation. Optical characterization reveals strong ultraviolet absorption, with estimated band-gap energies of 3.61–3.71 eV. The optimized 3 mM IrSb₃ TFT exhibits a field-effect mobility of 1.05 cm² V⁻¹ s⁻¹, a current on/off ratio of 9.72 × 10⁶, a threshold voltage of 2.39 V, and a subthreshold swing of 0.73 V/dec. Temperature-dependent measurements from 50 to 300 °C reveal comparatively stable transport in the optimized device, with Vth varying from 2.95 to 2.01 V (|ΔVth| = 0.94 V) and SS from 0.681 to 0.721 V/dec (ΔSS = 0.040 V/dec). In contrast, the 0.5 mM device exhibits substantially stronger thermal sensitivity, with |ΔVth| = 4.32 V and ΔSS = 0.465 V/dec. Activation-energy analysis yields peak Ea values of approximately 0.30–0.32 eV for the optimized device and 0.20–0.22 eV for the low-molarity device, supporting distinct morphology-dependent transport regimes. To the best of our knowledge, this work represents the first demonstration of nanostructured IrSb₃ skutterudite thin films as active TFT channels, establishing a direct relationship between nanostructure evolution and temperature-dependent transistor transport.