Room temperature LPG sensor based on n-CdS/p-polyaniline heterojunction

In the present work, room temperature (300 K) liquefied petroleum gas (LPG) sensor based on n-CdS/p-polyaniline thin film heterojunction has been fabricated using simple inexpensive electrodeposition technique. The CdS and polyaniline films were characterized for their structural and surface morphological properties and LPG sensing performance of n-CdS/p-polyaniline heterojunction was studied. The X-ray diffraction (XRD) study revealed polycrystalline cubic phase for CdS films whereas the polyaniline films exhibited amorphous structure. Morphological analysis using field-emission scanning electron microscopy (FESEM) of the junction cross-section revealed the formation of a diffusion-free interface. The room temperature gas response towards N2, CO2 and LPG was investigated and found to exhibit high response towards LPG as compared to N2 and CO2. The maximum gas response of 80% was achieved with 95% stability for n-CdS/p-polyaniline heterojunction upon exposure of 1040 ppm LPG at room temperature.