Flexible x-ray imaging detector based on direct conversion in amorphous selenium

In this paper, the authors propose a mechanically flexible direct conversion x-ray detector as a potential solution for portable and conformal digital x-ray imaging. It consists of a micropillar structured layer of 100-μm-thick amorphous selenium (a-Se) on a flexible thin film transistor (TFT) backplane with a pixel size of 70 μm as a substrate. The flexible substrate is made of an optically transparent polyimide with a heat resistance of more than 200 °C. It is bonded on a glass carrier for rigid substrate handling during the amorphous silicon (a-Si) TFT process. Separating the flexible substrate from the glass carrier is partly facilitated by a debonding layer sandwiched between them. A two-dimensional electrical simulation analysis revealed a possible charge generation and collection mechanism within the micropillared a-Se layer. An x-ray image captured by the curved flexible detector indicated that a pillarlike a-Se conversion layer can be used to perform x-ray imaging. This is, to the best of our knowledge, the first demonstration of a flexible digital x-ray direct conversion detector.