CW laser beam-based reduction of graphene oxide films for gas sensing applications

In this study we present a room-temperature direct reduction of graphene oxide (GO) thin films using a laser. Our suggested method reduces solution-processed GO film onto substrate non-thermally using a continuous wave (CW) laser beam, using low laser power (15 mW), and low irradiation time (1 min.) compared with other laser reduction techniques. The characteristic broad peaks at 1360 and 1608 cm−1 corresponding to D and G bands of the reduced GO lattice, respectively, were observed in the Raman spectra of all samples, and their relative intensities were found to be influenced by the laser power and the exposure time. Besides being selective, fast, and non-contact operation without catalyst, this approach is cost-effective because of utilizing a CW laser beam instead of the expensive picosecond or femtosecond laser systems and using a low power laser source comparing with the methods published in the last two years. Then, we created a vertically aligned SiNWs gas sensor that was geared towards detecting ammonia (NH3) and carbon monoxide (CO) gas at mid-infrared (MIR) wavelengths. On Si wafers, SiNWs with a diameter of just 200 nm were developed. (MIR) gas sensing is particularly helpful and user-friendly since it detects gases immediately as they pass through the sensor’s active detecting region, preventing human contact with potentially dangerous chemicals.