25.3: Flexible In‐cell Infrared a‐Si Sensor

Abstract

AbstractIn this work, an in‐cell photosensor was fabricated on a flexible display backplane for infrared sensing utilizations, such as optical touch panel, pen‐writing input function, and so on. The IR responsivity of a hydrogenated amorphous silicon thin film transistor was characterized under near‐infrared illuminations of 850 nm and 940 nm wavelengths. A compact active pixel sensor integrating the photo transistor was embedded into the display cell array. The experimental results demonstrate that a photocurrent to dark current ratio above 103, and an infrared sensitivity of 0.2 V/(s·W·m2) of the in‐cell active pixel sensor were obtained. With the advantages of process compatibility, flexibility and low fabrication cost of scaling‐up, the flexible in‐cell infrared sensor can be a very promising optical detector for all kinds of applications.