Indium phosphide nanowires: Synthesis and integration into a gas sensing device

Highlights •Successful synthesis of indium phosphide nnanowires with a diameter of 87 nm and relatively narrow size distribution.•Phase purity of the indium nanowires was important to ensure best possible performance and this was achieved.•Interaction between different analyte gases and the surface binding sites of indium phosphide nanowires were successfully investigated using Temperature-Programmed Desorption (TPD) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS).•Methane gas (CH4) was found to physically adsorb on the surface of indium nanowires through weak van der Waals interaction while on the other hand electron transfer between the CO and indium phosphide nanowires led to a chemical bond formation.•Carbon monoxide showed the fastest response time of 27 s at 250 °C and this was the quickest of all the analyte gases tested. [Display omitted] Indium phosphide nanowires (InPNWs) with an average diameter of 87 nm were successfully synthesised through thermal chemical vapour deposition (CVD) method. The smooth surface nanowires showed a relatively narrow size distribution of 70–105 nm. Temperature programmed desorption (TPD) was used to study the thermodynamic behaviour of gas desorption. The study revealed that gaseous CO and CH4 molecules bind to InPNW surface through chemical and physical adsorption, respectively. The Redhead method was used to estimate the enthalpy energy of desorption for CO and CH4 to be 142 kJ/mol and 38 kJ/mol. The sorption temperature ranges were found to be 220–260 ̊C for CO and -50 to -20 ̊C for CH4. InPNWs were used to fabricate a gas sensor electronic device and were tested for performance. The device showed a quick response time of 29.19 s for CO at 250 ̊C, thus relatively faster than that of H2 and NO2.