Highly Photosensitive Dual-Gate a-Si:H TFT and Array for Low-Dose Flat-Panel X-Ray Imaging

Amorphous silicon thin-film transistors (TFTs) have been widely used to build flat-panel X-ray detectors for medical imaging. To meet the growing demand for low dose and high sensitivity, attention has been paid to active pixel sensor (APS) with high signal-to-noise-ratio (SNR). However, most APS architectures generally require multiple TFTs in one pixel, resulting in low fill factor, low spatial resolution, and discounted SNR. We proposed a smart pixel architecture based on a dual-gate photosensitive TFT that combines sensor, switch, and storage into one TFT intended for high fill factor, high spatial resolution, and high SNR. This letter aims to investigate the sensitivity and noise performance of the smart pixel along with the evaluation of the first 4×4 smart pixel sensor array.