Dataset for Effect of Subthreshold Slope on the Sensitivity of Nanoribbon Sensors

In this work, we investigate how the sensitivity of a nanowire or nanoribbon sensor is influenced by the subthreshold slope of the sensing transistor. Polysilicon nanoribbon sensors are fabricated with a wide range of subthreshold slopes and the sensitivity is characterized using pH measurements. It is shown that there is a strong relationship between the sensitivity and the device subthreshold slope. The sensitivity is characterized using the current sensitivity per pH, which is shown to increase from 1.2% to 33.6% as the subthreshold slope improves from 6.2 V/dec to 0.23 V/dec respectively. We propose a model that relates current sensitivity per pH to the subthreshold slope of the sensing transistor. The model shows that sensitivity is determined only on the sub-threshold slope of the sensing transistor and the choice of gate insulator. The model fully explains the values of current sensitivity per pH for the broad range of subthreshold slopes obtained in our fabricated nanoribbon devices. It is also able to explain values of sensitivity reported in the literature, which range from 2.5%/pH to 650%/pH for a variety of nanoribbon and nanowire sensors. For the first time, the proposed model therefore provides a figure-of-merit for comparing the performance of nanoscale field effect transistor sensors fabricated using different materials and technologies.

本研究探讨了纳米线（nanowire）或纳米带（nanoribbon）传感器的灵敏度受感测晶体管亚阈值摆幅（subthreshold slope）的影响规律。本研究制备了亚阈值摆幅覆盖范围宽泛的多晶硅（polysilicon）纳米带传感器，并通过pH测试对其灵敏度进行表征。结果表明，传感器灵敏度与器件亚阈值摆幅之间存在显著关联。本次研究采用每pH电流灵敏度作为灵敏度表征指标，结果显示，当亚阈值摆幅从6.2 V/dec优化至0.23 V/dec时，该灵敏度可从1.2%提升至33.6%。本研究提出了一种将每pH电流灵敏度与感测晶体管亚阈值摆幅相关联的理论模型。该模型表明，传感器灵敏度仅由感测晶体管的亚阈值摆幅以及栅绝缘体（gate insulator）的选型决定。该模型可完整解释本研究制备的纳米带器件中，宽泛亚阈值摆幅区间内的每pH电流灵敏度数值。同时，该模型还可解释已发表文献中报道的各类纳米带与纳米线传感器的灵敏度数值，其覆盖范围为2.5%/pH至650%/pH。综上，本研究提出的模型首次为对比不同材料与工艺制备的纳米级场效应晶体管（nanoscale field effect transistor）传感器的性能提供了统一的品质因数（figure-of-merit）评价标准。