Influence of Deposition Duration on the Morphological Evolution of Electrodeposited Copper Selenide Films

This study investigates the growth process and thermoelectric properties of electrodeposited Cu2Se films. The growth mechanism revealed that morphology, stoichiometry, Seebeck coefficient (S), and electrical conductivity (σ) all vary with film thickness. Voltammetric results showed a consistent appearance and variation of the anodic peak, highlighting its role in defining the electrochemical window for the controlled co-deposition of Cu and Se, which is crucial for developing semiconductors. SEM analysis revealed that the film morphology strongly depends on deposition time. Microstructural analysis demonstrated a distinct evolution in the film growth mechanism, starting with an early-stage transition from layer-plus-island-like growth. EDX and XRD analyses indicated changes in atomic composition during growth, beginning with a Se-rich mixture of Cu-Se phases. The electrical conductivity (σ) of the films increased as the layer thickness decreased. The Seebeck coefficient (S) increases with film thickness, reaching an optimal value of +16 µV/K at 10.5 µm.