Experimental study of AlGaN/GaN HEMT based devicesfor gas sensing applications

• Main Author: Jahan, Fina
• Other Authors: K. Radhakrishnan
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Semiconductors
• Online Access: http://hdl.handle.net/10356/76366
• Institution: Nanyang Technological University

In recent times, gas sensing applications have seen an increased demand in both manufacturing industries and research studies. This project aims to study high electron mobility transistors (HEMT) and their abilities, as well as the properties of two dimensional electron gas (2DEG) and III nitrides, specifically aluminium gallium nitride (AlGaN) and gallium nitride (GaN). Upon understanding these properties, gas sensing experiments were carried out in order to understand how the devices have responded to various factors such as temperature and relative humidity. Gases which were used are namely nitrogen dioxide (NO2) and ammonia (NH3).Sample devices were tested with NH3 under varying temperature values ranging from room temperature to 280°C. Likewise, the device was tested with NO2 under varying humidity ranges. At room temperature, the resistance increased with increasing concentrations of NH3 and was the highest change of resistance compared to other temperature inputs. Temperature dependent response have been observed for NH3. For NO2 measurements, the devices experienced an increase in resistance when the device was exposed to the gas under the presence of humidity. This indicated that the response was sensitive to humidity.