Ferroelectric perovskites are an important group of materials underpinning a wide variety of devices ranging from sensors and transducers to nonvolatile memories and photovoltaic cells. Despite the progress in material synthesis, ferroelectric characterization of nanoscale perovskites is still a challenge. Piezoresponse force microscopy (PFM) is one of the most popular tools for probing and manipulating nanostructures to study the ferroelectric properties. However, the interpretation of hysteresis data and alternate signal origins are critical. Here, we use a family of scanning probe microscopy (SPM) techniques to systematically investigate the ferroelectric behavior of electrospun potassium niobate (KNbO₃) nanofibers. Band Excitation (BE) SPM scans reveal that PFM signals are dominated by changes in resonant frequency due to rough nanofiber surfaces, rather than the actual local piezoelectric strength. We investigate the bias-induced charge injection properties and electrostatic interactions on the PFM response of the nanofiber using contact mode Kelvin probe force microscopy (cKPFM). Furthermore, the impact of relative humidity on the KNbO₃ nanofiber’s piezoresponse, switching behavior, and tip-induced charges are explored. The resultant data from BE scans were utilized to estimate the piezoelectric constants of the KNO nanofiber. These observations will provide clarity in studying newly developed ferroelectric nanostructures and unambiguously interpreting the PFM data.

中文翻译：

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钙钛矿纳米纤维中的表观铁电解码

铁电钙钛矿是一组重要的材料，可支撑从传感器和换能器到非易失性存储器和光伏电池等各种设备。尽管材料合成方面取得了进展，但是纳米钙钛矿的铁电表征仍然是一个挑战。压电响应力显微镜（PFM）是探测和操纵纳米结构以研究铁电特性的最受欢迎的工具之一。但是，磁滞数据和备用信号源的解释至关重要。在这里，我们使用扫描探针显微镜（SPM）技术家族来系统地研究电纺铌酸钾（KNbO ₃）纳米纤维。带激励（BE）SPM扫描显示，PFM信号主要是由于纳米纤维表面粗糙而引起的共振频率变化，而不是实际的局部压电强度。我们使用接触模式开尔文探针力显微镜（cKPFM）研究了纳米纤维的PFM响应上的偏压诱导的电荷注入特性和静电相互作用。此外，还研究了相对湿度对KNbO ₃纳米纤维的压电响应，开关行为和尖端感应电荷的影响。来自BE扫描的结果数据被用于估计KNO纳米纤维的压电常数。这些观察结果将为研究新开发的铁电纳米结构和明确解释PFM数据提供清晰的信息。