Abstract:
P-type cuprous oxide thin films electrodeposited on a titanium substrate in a lactate bath was investigated for
liquid petroleum gas (LPG) sensing. Contact angle measurements using water droplets revealed that the surfaces
of the films become progressively hydrophobic with increasing deposition bath pH. The films deposited at pH =
10 were sensitive for LPG even at room temperature (30 ◦C). X-ray diffraction (XRD) and scanning electron
microscopy (SEM) were performed to investigate the crystalline structure and the surface morphology of Cu2O
films. According to the XRD patterns, the films had a preferred orientation along the (200) and (111) planes.
The normalized intensity of (200) XRD peak increased with the deposition bath pH and reached its maximum
value around pH = 11. It was also observed that the LPG sensitivity of the Cu2O films closely followed the
normalized intensity of (200) peak. SEM images of Cu2O films showed the presence of well-defined crystallites
with sharp edges. Atomic force microscopy (AFM) analysis showed that the surface roughness increased with
deposition bath pH. Energy Dispersive X-ray analysis (EDAX) was used for compositional analysis of films and
Mott - Schottky plots and spectral response measurements were carried out to confirm the p-type conductivity.
