Giant piezoresistance effect of P-type silicon nanowires

Silicon nanowires (SiNWs) are promising for mechanical sensors due to their excellent piezoresistance effect. The geometric dimensions and doping concentration of SiNWs are key factors when optimizing the sensitive structure of the sensor. In this study, a simulation framework based on drift-diffusion (DD) model has been constructed to simulate the giant piezoresistance of SiNWs. The giant piezoresistance effect in P-type SiNWs is fully investigated by simulating different geometric dimensions and doping concentrations, giving guidance in the sensitive structure design. Within the studied dimensional range, SiNWs with a larger aspect ratio demonstrate better piezoresistance properties. For example, the piezoresistance coefficient (Π) of SiNWs with L = 0.5 μm and W = 0.05 μm shows a value of 782 × 10⁻¹¹ Pa⁻¹ and that of SiNWs with L = 2 μm and W = 0.05 μm shows a value of 1060 × 10⁻¹¹ Pa⁻¹. Besides, the SiNWs with a higher doping concentration of 1 × 10¹⁶ cm⁻³ exhibit 3–5 times larger Π compared to it with 1 × 10¹⁴ cm⁻³ doping concentration in the stress range of 0–100 MPa. This study provides a detailed analysis of the relationship between stress, geometric dimensions, and doping concentration, offering theoretical insights for the design and optimization of high-sensitivity SiNWs piezoresistance sensors.