Potyrailo Radislav A, Leach Andrew, Morris William G, Gamage Sisira Kankanam
Materials Analysis and Chemical Sciences, General Electric Global Research Center, Niskayuna, New York 12309, USA.
Anal Chem. 2006 Aug 15;78(16):5633-8. doi: 10.1021/ac052086q.
We demonstrate an approach for the development of chemical sensors utilizing silicon micromachined physical transducers with integrated piezoresistive readout. Originally, these transducers were developed and optimized as sensitive accelerometers for automotive applications. However, by applying a chemically responsive layer onto the transducer, we convert these transducers into chemical sensors. These transducers are attractive for chemical sensing applications for several key reasons. First, the required sensitivity of the chemical sensor can be achieved by choosing the right spring constant of the transducer. Second, the integrated piezoresistive readout of the transducer is already optimized and is very straightforward, providing a desired reproducibility in measurements, while not requiring bulky equipment. Third, chemically responsive film deposition is simple due to the ease of access to the transducer's surface. Fourth, such transducers are already available for another (automotive) application, making these sensors very cost-effective. The applicability of this approach is illustrated by the fabrication of highly sensitive CO2 sensors. To study hysteresis effects, we selected high CO2 concentrations (10-100% CO2) to provide the worst-case scenario for the sensor operation. These sensors demonstrate a hysteresis-free performance over the concentration range from 10 to 100% vol CO2, have detection limits of 160-370 ppm of CO2, and exhibit a relatively rapid response time, T(90) = 45 s. Importantly, we demonstrate a simple method for cancellation of vibration effects when these physical transducers, initially developed as accelerometers, are applied as chemical sensors.
我们展示了一种利用带有集成压阻式读出的硅微机械物理传感器开发化学传感器的方法。最初，这些传感器是作为用于汽车应用的灵敏加速度计而开发和优化的。然而，通过在传感器上施加化学响应层，我们将这些传感器转变为化学传感器。这些传感器因其几个关键原因而在化学传感应用中颇具吸引力。首先，通过选择合适的传感器弹簧常数可以实现化学传感器所需的灵敏度。其次，传感器的集成压阻式读出已经得到优化且非常直接，在测量中提供了所需的可重复性，同时不需要笨重的设备。第三，由于易于接触到传感器表面，化学响应膜的沉积很简单。第四，这种传感器已经可用于另一种（汽车）应用，使得这些传感器非常具有成本效益。通过制造高灵敏度的二氧化碳传感器来说明这种方法的适用性。为了研究滞后效应，我们选择了高二氧化碳浓度（10 - 100%二氧化碳）来为传感器运行提供最坏情况。这些传感器在10%至100%体积分数的二氧化碳浓度范围内表现出无滞后性能，二氧化碳检测限为160 - 370 ppm，并且响应时间相对较快，T(90) = 45秒。重要的是，当这些最初作为加速度计开发的物理传感器用作化学传感器时，我们展示了一种消除振动影响的简单方法。
