Indium content dependent VOCs interactions in monolithic InGaN/GaN multi quantum well structures grown by MOCVD

In this study, indium concentration dependence on Volatile Organic Compounds (VOCs) interaction were examined in InGaN-GaN multi quantum well structures (MQWs) grown on sapphire substrate at different quantum well (InGaN) growth temperatures. The periodicity, structural properties and indium dependent dislocation density was deduced from high resolution X-ray diffraction pattern. The variation of energy bandgap of InGaN quantum well clearly depicts that the bandgap decreases with increase in indium concentration in InGaN well layer. The interaction properties of the device with various VOCs such as ethanol, benzene, n-hexane and triethylamine were examined using Scanning Kelvin Probe (SKP) system and they are correlated with dislocation density. The change in contact potential difference (CPD) in dark and visible light illumination, as well as the variation of CPD with respect to various VOCs is observed. The difference in contact potential difference clearly suggests that the InGaN-GaN multi quantum well structure can be one of the suitable candidates for novel gas sensor applications.