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Epitaxial Liftoff of Wafer‐Scale VO <sub/>2</sub> Nanomembranes for Flexible, Ultrasensitive Tactile Sensors
摘要： Highly sensitive tactile sensors with long-term stability and low power consumption are one of the key components for flexible electronics. Here, for the first time, the fabrication of VO2 nanomembrane tactile sensors by epitaxial liftoff from ZnO sacrificial layer is reported. The wafer-scale nanomembranes inherit the structural and electrical properties of the as-grown films, and the wet transfer generates negligible influence on the quality of VO2. Most importantly, giant electrical responses to external strains are found due to the release of substrate clamping, and a high gauge factor up to ≈1100 is derived. Furthermore, the electrical properties show no deterioration after repeatedly bending the nanomembranes for 10 000 times at a radius of 1 cm. The VO2 nanomembrane sensors are utilized to monitor the radial artery pulse, and totally reproducible waveforms with ultrahigh sensitivity to the tactile stimuli are observed. Moreover, the power dissipation of the VO2 tactile sensors can be lowered down to the picowatt level, allowing for the future construction of self-powered sensing systems together with nanogenerators. This study provides a substantial step toward large-scale preparation of oxide nanomembranes and therefore paves a promising way for flexible oxide electronics.
关键词： flexible electronics,piezoresistivity,vanadium dioxide,tactile sensors,epitaxial liftoff
更新于2025-11-14 17:03:37
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Experimental Characterization of the Influence of Transverse Prestrain on the Piezoresistive Coefficients of Heavily Doped n-Type Silicon
摘要： Strain has been integrated into many silicon devices, as it has an essential impact on carrier mobility and crystal symmetry. Those parameters respond differently under both biaxial and uniaxial, so their effect needs to be quantified to successfully employ the strain engineering in different silicon applications. As an extended step toward utilizing strain in enhancing the sensitivity and the temperature independency of a 3-D stress sensor, the effect of uniaxial transverse strain onto the piezoresistive (PR) coefficients of heavily doped n-type silicon will be experimentally characterized. A new design was developed to apply the transverse tensile and compressive uniaxial stresses onto the silicon substrate using a highly compressive nitride layer. This stressing technique was integrated with six PR elements rosette to fully calibrate the PR coefficients, where unstrained, tensile, and compressive strained PRs are fabricated within the same chip to accurately quantify the strain impact. Four-point bending, stress-free temperature, and hydrostatic test were used to typically measure the PR coefficients. Strain values of 0.065% and 0.083% ε were achieved locally using both the tensile and compressive stressors, respectively. Under this level of strain, the typical result shows opposite impact for both the tensile and compressive transverse strains on the longitudinal and transverse PR coefficients. Moreover, an increase up to 80% can be achieved for the pressure coefficient of heavily doped n-type silicon due to the compressive transverse strain.
关键词： metal–oxide–semiconductor (MOS) local transistors,3-D piezoresistive (PR) sensor,n-type silicon,strain,strain engineering,piezoresistivity
更新于2025-09-09 09:28:46