Dependence of structure and electrical properties on growth temperature in PVD tellurium nano-thin films

Tellurium (Te) has recently gained attention due to its unique one-dimensional helical chain crystal structure and promising optoelectronic and thermoelectric properties. In this study, we investigate the influence of substrate temperature (296 K-326 K) on the structural and electrical characteristics of ~20 nm Te films deposited via vacuum thermal evaporation on Si/SiO₂ substrates. Morphological analysis using atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) revealed correlation between the substrate temperature and the changes in the structure from trapezoidal to elongated stick-like features. Xray diffraction and Raman spectroscopy demonstrated that the Te chains were predominantly oriented parallel to the substrate surface at TS = 326 K. The chain length and packing density were dependent on TS. Spatially resolved current-voltage measurements show a strong temperaturedependent decrease of the in-plane charge transport, whereas higher-temperature films were characterized by an increased lateral resistance. Scanning Kelvin probe microscopy measurements further reveal surface potential differences of ~0.6 V between samples. These results demonstrate that small variations in substrate temperature can significantly modulate nanoscale morphology and electrical transport, providing a route to engineer Te-based thin-film devices with tailored performance.