Effect of microstructures on the electrical and optoelectronic properties of nanocrystalline Ta-Si-N thin films by reactive magnetron cosputtering

The evolution of an amorphous-like to a polycrystalline microstructure and the composition of Ta-Si-N nanocomposites was controlled by nitrogen flow ratios during reactive cosputtering. It influences the chemical bonding, electrical resistivity and optoelectronic luminescent properties of Ta-Si-N films. Amorphous-like Ta-Si-N films formed at a Si/(Si + Ta) ratio larger than 6% had much finer grains, smoother morphology, lower Ta 4f^7/2 binding energy and lower resistivity compared to polycrystalline films. A strong visible photoluminescence was observed at Ta₅₃Si₇N₄₀ compositions for a peak maximum at 554 nm (2.24 eV).