Impact of Hole Gas in O₂ Sensing Applications in Ge Core Si Shell Nanowires: Quantum Simulation Study

In this study, we investigate the impact of hole gas on the performance of sensing applications using Germanium (Ge) core Silicon (Si) shell nanowires (NWs) through quantum simulation. The unique core-shell structure of Ge/Si NWs offers significant advantages in sensing due to its enhanced electronic properties and high surface-to-volume ratio. Using advanced quantum mechanical modeling and simulation techniques, we analyze the energy band, wave functions profiles, spatial composition of hole concentration, charge transport characteristics and sensitivity under varying conditions. The study provides detailed insights into the quantum mechanical interactions and charge transport mechanisms within the Ge/Si NW, highlighting the potential for these nanostructures in developing highly sensitive and efficient sensors. Our findings demonstrate that formation of a hole gas within the undoped Ge core, while the Si shell is doped with an acceptor impurity. As the gate work function changes on application of gas, holes migrate toward the Si shell due to stronger valence band bending. This shift enhances changes charge transport, improves device sensitivity and ascertains that the manipulation of hole gas within the Ge core can be a key factor in enhancing the performance of gas-sensors, paving the way for the development of next-generation diagnostic tools.