The ability to control surface–analyte interaction allows tailoring chemical sensor sensitivity to specific target molecules. By adjusting the bias of the shallow p–n junctions in the electrostatically formed nanowire (EFN) chemical sensor, a multiple gate transistor with an exposed top dielectric layer allows tuning of the fringing electric field strength (from 0.5 × 10⁷ to 2.5 × 10⁷ V/m) above the EFN surface. Herein, we report that the magnitude and distribution of this fringing electric field correlate with the intrinsic sensor response to volatile organic compounds. The local variations of the surface electric field influence the analyte–surface interaction affecting the work function of the sensor surface, assessed by Kelvin probe force microscopy on the nanometer scale. We show that the sensitivity to fixed vapor analyte concentrations can be nullified and even reversed by varying the fringing field strength, and demonstrate selectivity between ethanol and n-butylamine at room temperature using a single transistor without any extrinsic chemical modification of the exposed SiO₂ surface. The results imply an electric-field-controlled analyte reaction with a dielectric surface extremely compelling for sensitivity and selectivity enhancement in chemical sensors.

中文翻译：

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带有边缘电场的内在传感器对挥发性有机化合物的响应控制

控制表面与分析物相互作用的能力可以针对特定目标分子定制化学传感器的灵敏度。通过调节静电形成的纳米线（EFN）化学传感器中浅p–n结的偏置，具有暴露的顶部介电层的多栅极晶体管可以调节边缘电场强度（从0.5×10 ⁷到2.5×10 ⁷V / m）。在这里，我们报告此边缘电场的大小和分布与本征传感器对挥发性有机化合物的响应相关。表面电场的局部变化影响分析物与表面的相互作用，从而影响传感器表面的功函数，通过开尔文探针力显微镜在纳米尺度上进行评估。我们表明，通过改变边缘场强度，可以消除对固定蒸气分析物浓度的灵敏度，甚至可以使灵敏度反转，并且证明了在室温下使用单个晶体管对乙醇和正丁胺之间的选择性，而无需对暴露的SiO ₂进行任何外在化学修饰表面。结果表明，电场控制的分析物反应具有介电表面，对于化学传感器中的灵敏度和选择性增强具有极强的吸引力。