Microstructured Porous Pyramid-based Ultra-high Sensitive Pressure Sensor Insensitive to Strain and Temperature.

An ultra-high sensitive capacitive pressure sensor based on porous pyramid dielectric layer (PPDL) is reported. Compared to that of the conventional pyramid dielectric layer, the sensitivity was drastically increased to 44.5 kPa-1 in the pressure range <100 Pa, an unprecedented sensitivity for capacitive pressure sensors. The enhanced sensitivity is attributed to lowered compressive modulus and larger change in effective dielectric constant under pressure. By placing the pressure sensors on islands of hard elastomer embedded in soft elastomer substrate, the sensors exhibited insensitivity to strain. The pressure sensors were also non-responsive to temperature. Finally, a contact resistance-based pressure sensor is also demonstrated by chemically grafting PPDL with a conductive polymer, which also showed drastically enhanced sensitivity.