Impedometric anion sensing behaviour of In <inf>x</inf> Ga <inf>1 - X</inf> N films grown by modified activated reactive evaporation

In the present work, In x Ga 1 - x N 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 KNO 3 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. © 2011 Elsevier B.V. All rights reserved.