The aim of this research work is to analyze the surface characteristics of an improved AlGaN/GaN HEMT biosensor. The investigation leads to analyze the transistor performance to detect human MIG with the help of an an...The aim of this research work is to analyze the surface characteristics of an improved AlGaN/GaN HEMT biosensor. The investigation leads to analyze the transistor performance to detect human MIG with the help of an analytical model and measured data. The surface engineering includes the effects of repeatability, influence of the substrate, threshold shifting, and floating gate configuration. A numerical method is developed using the charge-control model and the results are used to observe the changes in the device channel at the quantum level. A Self-Assembled Monolayer (SAM) is formed at the gate electrode to allow immobilization and reliable cross-linking between the surface of the gate electrode and the antibody. The amperometric detection is realized solely by varying surface charges induced by the biomolecule through capacitive coupling. The equivalent DC bias is 6.99436 × 10<sup>-20</sup> V which is represented by the total number of charges in the MIG sample. The steady state current of the clean device is 66.89 mA. The effect of creation and immobilization of the protein on the SAM layer increases the current by 80 - 150 μA which ensures that successful induction of electrons is exhibited.展开更多
The paper presents a polycrystalline GaN thin film with a hexagonal wurtzite structure under the optimized sputtering conditions of 40 W RF power, 5 mT working pressure, using pure nitrogen gas with a substrate temper...The paper presents a polycrystalline GaN thin film with a hexagonal wurtzite structure under the optimized sputtering conditions of 40 W RF power, 5 mT working pressure, using pure nitrogen gas with a substrate temperature of 700°C. The study examines the effects of surface disorders and incorporates it in the thin films characteristics. A radio frequency (RF) Ultra High Vacuum (UHV) Magnetron Sputtering System has been used for the deposition of Gallium Nitride (GaN) on silicon, sapphire and glass substrates with different parameters. The power is varied from 40 W to 50 W, and the pressure from 4 mT to 15 mT. The effects of the RF sputtering powers and gas pressures on the structural properties are investigated experimentally. Sputtering at a lower RF power of 15 W does increase the N atomic percentage, however the deposition rate is substantially slower and the films are amorphous. GaN deposited on both silicon and sapphire wafer resulted in thin films close to stoichiometric once the N2 concentration is 60% or higher. It is also observed that the substrate cooling/heating effects improve the quality of the thin films with fewer defects present at the surface of the GaN epi-structure.展开更多
文摘The aim of this research work is to analyze the surface characteristics of an improved AlGaN/GaN HEMT biosensor. The investigation leads to analyze the transistor performance to detect human MIG with the help of an analytical model and measured data. The surface engineering includes the effects of repeatability, influence of the substrate, threshold shifting, and floating gate configuration. A numerical method is developed using the charge-control model and the results are used to observe the changes in the device channel at the quantum level. A Self-Assembled Monolayer (SAM) is formed at the gate electrode to allow immobilization and reliable cross-linking between the surface of the gate electrode and the antibody. The amperometric detection is realized solely by varying surface charges induced by the biomolecule through capacitive coupling. The equivalent DC bias is 6.99436 × 10<sup>-20</sup> V which is represented by the total number of charges in the MIG sample. The steady state current of the clean device is 66.89 mA. The effect of creation and immobilization of the protein on the SAM layer increases the current by 80 - 150 μA which ensures that successful induction of electrons is exhibited.
文摘The paper presents a polycrystalline GaN thin film with a hexagonal wurtzite structure under the optimized sputtering conditions of 40 W RF power, 5 mT working pressure, using pure nitrogen gas with a substrate temperature of 700°C. The study examines the effects of surface disorders and incorporates it in the thin films characteristics. A radio frequency (RF) Ultra High Vacuum (UHV) Magnetron Sputtering System has been used for the deposition of Gallium Nitride (GaN) on silicon, sapphire and glass substrates with different parameters. The power is varied from 40 W to 50 W, and the pressure from 4 mT to 15 mT. The effects of the RF sputtering powers and gas pressures on the structural properties are investigated experimentally. Sputtering at a lower RF power of 15 W does increase the N atomic percentage, however the deposition rate is substantially slower and the films are amorphous. GaN deposited on both silicon and sapphire wafer resulted in thin films close to stoichiometric once the N2 concentration is 60% or higher. It is also observed that the substrate cooling/heating effects improve the quality of the thin films with fewer defects present at the surface of the GaN epi-structure.
