Highly sensitive formaldehyde resistive sensor based on a single Er-doped SnO2 nanobelt

SnO2 nanobelts (SnO2 NBs) and Er3+-doped SnO2 nanobelts (Er–SnO2 NBs) were synthesized by thermal evaporation. The obtained samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersion spectrometer (EDS), and X-ray photoelectron spectrometer (XPS). It is found that Er–SnO2 NBs have a good morphology with smooth surface and their thickness are about 30 nm, widths between 200 nm and 600 nm, and lengths 30–80 mm. The nanobelts with good morphology were taken to develop sensors based on a single Er–SnO2 NB/SnO2 NB for studying sensitive properties. The results reveal that the response of a single Er–SnO2 nanobelt device is 9 to the formaldehyde gas with a shorter response (recovery time) of 17 (25) s.