For pragmatic utilizations of field-effect transistors (FETs), the control of threshold voltage (V_th) is significant for sensing applications as various sensors and circuits require distinctive electrical characteristics. Moreover, the controllable threshold voltage is essential for creating integrated circuits (IC). The threshold voltage of a TFT is sensitive to numerous factors, which make it alluring for sensing applications. However, its estimation is not simple, particularly when mobility is field-dependent and source/drain resistances are noteworthy. Precise control of the threshold voltage in organic FETs also remains challenging. Conventionally, for an organic transistor threshold voltage is typically an empirical parameter that is obtained by fitting the experimental current–voltage transfer characteristics, which is temperamental as it relies upon the range of the gate bias. However, the turn-on voltage of a transistor is not affected from these downsides and therefore suggests an alternative that can be used for sensing applications. Customary, measurement of on-state voltage requires the estimation of current in the subthreshold region and its extrapolation at the voltage axis, which it is normally not utilized. The present work analyzes the threshold voltage extracted using differential and conventional methods and the turn-on voltage extracted using the floating probe technique which is straightforward and requires the estimation of voltage at the floating terminal as the source voltage is linearly sloped while sustaining gate voltage constant. Two-dimensional numerical simulation results are introduced to support that the floating probe procedure yields reliable parameters than the threshold voltage and subsequently can be suitably used for sensing applications. Experimental results obtained with pentacene based top-contact organic TFT’s (OTFTs) are also shown to delineate the proposed idea.

为了实用地利用场效应晶体管（FET），控制阈值电压（V _th）对于各种传感应用和电路需要独特的电气特性，对于传感应用具有重要意义。此外，可控阈值电压对于创建集成电路（IC）至关重要。TFT的阈值电压对许多因素敏感，这使其对传感应用很有吸引力。但是，其估算并不简单，尤其是在迁移率与场有关且源/漏电阻很重要的情况下。精确控制有机FET中的阈值电压也仍然具有挑战性。传统上，对于有机晶体管，阈值电压通常是通过拟合实验电流-电压传递特性而获得的经验参数，该特性是气质的，因为它依赖于栅极偏置的范围。然而，晶体管的导通电压不受这些不利影响的影响，因此提出了一种可用于传感应用的替代方案。通常，通态电压的测量需要估算亚阈值区域中的电流并在电压轴上对其进行外推，这通常是不使用的。本工作分析了使用差分和常规方法提取的阈值电压以及使用浮动探针技术提取的开启电压，该方法很简单，并且由于源极电压在保持栅极电压恒定的同时线性倾斜，因此需要估算浮动端子上的电压。引入了二维数值模拟结果，以支持浮动探针程序可产生比阈值电压可靠的参数，并且随后可适用于感测应用。还显示了使用并五苯基于顶部接触的有机TFT（OTFT）获得的实验结果来描述提出的想法。