Behavior of Mercury Ion Adsorption at AlGaN Surface and AlGaN/GaN Heterostructure Device Performance: First‐Principles and TCAD Study

Heavy metal ions are toxic to the environment and the human body, so it is particularly important to develop sensor technology that can detect them quickly. However, the existence period of the preparation and testing device is long, the cost is high, and there is secondary pollution to the environment during the configuration of heavy metal solution. Therefore, the simulation calculation method can improve the efficiency and protect the environment by conducting preliminary research on the adsorption characteristics of materials and device characteristics. In this paper, AlGaN/GaN HEMT devices are used to detect heavy metal mercury ions by sensing the change of surface potential. First, based on density functional theory (DFT) and first principles, the change of material properties caused by the adsorption of mercury ions to the AlGaN surface is obtained. It is calculated that the band gap of the material decreases by 0.245 eV after the adsorption of one mercury ion. Then, the TCAD tool was used to construct the AlGaN/GaN HEMT device model, and the output current of the HEMT device was increased by 10.162 mA by correcting the characteristic parameters of the material so as to realize the detection of heavy metal mercury ions, providing reference for the preparation and development of heterostructure HEMT devices based on AlGaN/GaN.