R.H. Bari

ABSTRACT

The objective of the present paper is to investigate the effect of dipping cycle interval (5, 10, and 15) on the structural, morphological, and gas sensing properties of nanostuctured CdO thin ?lms prepared by simple sol-gel deposition technique. The structural, microstructural and elemental composition have been revealed by X-ray diffractogram (XRD), field emission scanning electron microscopy (FE-SEM), and energy dispersive spectrophotometer (EDAX) respectively. The nanostructured CdO film showed selectivity for ethanol over methanol compared to ammonia (Sethanol /S methanol = 6.4 and Sethanol/S ammonia = 31.24). It is found that the sensing response increased monotonically with increasing operating temperature and gas concentration. The maximum ethanol response of 1353 for the sample S2 for gas concentration of 500 ppm at 300 oC was achieved. The quick response (TResponse = 4 s) and fast recovery (TRecovery = 9 s) are the main features of this film. Moreover, the repeatability of the experiments was tested for the most sensitive sample (S2). Additionally, the stability of the prepared sensor has been studied. Effect of dipping cycle interval on physical, structural, microstructural, electrical and gas sensing properties of these films were studied and presented in the present investigation. Keywords: Sol-gel technique, Nanostuctured CdO, surface morphology, thin films, organic vapour, gas response, selectivity.