Thin films of doped TCO for PN junction applications

Transparent conductive oxides (TCOs), combining optical transparency and electrical conductivity, are essential for thin-film photovoltaic technologies. This work explores the synthesis of undoped and doped (Li, V, Gd) ZnO thin films by chemical spray pyrolysis, with a view to their integration into PN junctions. Atom probe tomography (APT) revealed a homogeneous Li distribution. Raman, FTIR, SEM, EDX and XPS analyses confirm the structure and composition of the films. Vanadium-doped films show a wurtzite structure, good transparency (400-1200 nm), a bandgap of 3.18-3.26 eV, and improved microhardness. Gadolinium doping modifies the morphology and maintains an optical transmission of 60-80% with a bandgap of 3.24-3.26 eV. Finally, the n-ZnO/p-Si heterojunctions produced show promising performances, confirming the interest of the layers for photovoltaic and optoelectronic applications.