Gate-engineered high-performance triple material gate AlGaN/GaN HEMT based biosensor for pH detection
摘要
The gate-engineered AlGaN/GaN HEMT with an AlN cap layer is proposed in this article for detecting potential hydrogen (pH). In this work, we introduce three gate structures for pH detection: Single Material Gate (SMG), Double Material Gate (DMG), and Triple Material Gate (TMG). The drain current sensitivity analysis is carried out for all three structures. We demonstrate the sensing mechanism used for three structures, and the Silvaco ATLAS TCAD simulation tool is employed to extract the relevant parameters. There is a significant improvement in the drain current (Id) and transconductance (gm) of the gate material-engineered structures over the conventional single-material gate structures due to the changes in the surface potential of the channel. The proposed gate-engineered HEMT is used to detect the pH values ranging from 2 to 9. A sensitivity analysis was conducted for all three structures. Three structures showed better current sensitivities SI (SMG) = 23.20 mA/mm/pH, SI (DMG) = 21.52 mA/mm/pH and SI (TMG) = 19.81 mA/mm/pH. The three devices exhibit better linearity, with a coefficient of determination (R2) of > 0.96. The voltage sensitivities were also determined as SV (SMG) = 44.2 mV/pH, SV (DMG) = 36.4 mV/pH, and SV (TMG) = 49.1 mV/pH at 10 mA/mm, exhibiting good linearity, with a coefficient of determination (R2) = 1, which confirms their pH detection capability, reliability, and robustness. These devices exhibit higher sensitivity in alkaline regions, comparable to that in acidic regions. In this study‚ the current sensitivity of the SMG device is the highest of the three devices‚ while the TMG structure performs the best in terms of electric field optimization‚ carrier transport efficiency‚ linearity‚ and sensing reliability․ These results suggest that the AlN-capped TMG structure can be a promising candidate for high-performance pH sensing applications․