Improvement in Sensitivity of InN Resitive Gas Sensor by Thickness Modulation for Liver Malfunction Application

The traces of sub-ppm ammonia in the human breath is useful for the detection of the liver condition in humans. In this work, we have fabricated two InN based gas sensors of different thickness of the sensing film T1 (40 nm) and T2 (60 nm) respectively by RF-MOMBE. The current variation response of 2 ppm NH3 gas on T1 is approximately 10 fold higher than T2. The current variation response for 0.5 ppm on T1 is 0.04% while T2 showed a negligible response. The change at the surface of InN epilayer will be more significant on the total conductivity of the thin layer as compared to the thick layer. Hence, the lower thickness of the InN epilayer has a higher response as compared to higher thickness. Therefore, lower thickness (40 nm) is suitable for the diagnosis of liver malfunction.