Volatile organic compound sensing using copper oxide thin films: Addressing the cross sensitivity issue

- CuO thin film was grown on quartz substrate using sol gel route.
- Gas sensing properties of CuO thin film was performed using a quasi-static system.
- Excellent response is obtained towards ethanol, methanol, acetone and 2-propanol.
- High response (%) and low response time(s) are achieved at optimized temperature.
- FFT and PCA were studied to address the cross sensitivity.

We have investigated the sensing characteristics of ethanol, methanol, acetone, and 2-propanol using wet chemical synthesized copper oxide (CuO) thin films deposited on fused quartz substrates. As compared to the volatile organic component (VOC) sensing characteristics of CuO films reported in recent literatures, our thin film sensors offer relatively higher response (%), lower optimized temperature (corresponds to highest response%), better stability, and faster response time. In order to address the cross-sensitivity towards these VOC sensing we had performed fast Fourier transformation (FFT) analyses of the resistance transients. The resultant data matrices extracted from these FFT analyses were used as input parameter in a linear unsupervised principal component analysis (PCA) pattern recognition technique. We have demonstrated that FFT combined with PCA is an excellent tool for differentiating these reducing gases.