Impedometric anion sensing behaviour of InxGa1 − xN films grown by modified activated reactive evaporation

In the present work, InxGa1 − xN films with different indium compositions (x = 0.88, 0.63, 0.36 and 0.18) were prepared on glass substrates using a commercially viable technique known as modified activated reactive evaporation. Electrochemical impedance was used to investigate the anion sensing properties of these films for KCl, KI and KNO3 salt solutions of different molar concentrations. The anion sensing behaviour of InGaN films is attributed to the presence of high n-type background carrier concentration and positively charged surface donor states. The InGaN based anion sensors were found to have good sensitivity with faster response and recovery time. The film with x = 0.63 was found to have the highest sensitivity for all the anions due to the presence of more active surface area together with large number of surface donor states.

► Impedometric anion sensing behaviour of InGaN thin films has been studied for the first time. ► The InGaN based anion sensors were found to have good sensitivity with faster response and recovery time. ► The film with 63% indium was found to have the highest sensitivity for all the anions due to the presence of large active surface area and donor states.