Atomic-layer chemical vapor deposition of SnO2 for gas-sensing applications

SnO2 layers are grown from SnCl4 and H2O at 180–300°C on quartz glass substrates by atomic-layer-chemical-vapor-deposition-like process. The layers are oxygen deficient, predominantly amorphous and contain chlorine residues. Their amorphization degree decreases with the growth temperature. All the layers are sensitive to CO in air. Perfectly amorphous scanning-force-microscopy-smooth ultrathin (<10 nm) layers are grown at 180°C. The gas sensitivity of the latter paves the way for monograin-equivalent conductometric sensors; the presence of a massive uniformity is favorable for sensor mechanisms studies.