Three-dimensional fin-shaped dual-gate photosenstive a-Si:H thin-film transistor for low dose X-ray imaging

This work reports on a novel dual-gate photosensitive amorphous silicon (a-Si:H) thin-film transistor (TFT) for low-level light detection. To enhance carrier collection and light absorption while maintaining decent switching performance, a three-dimensional (3D) fin-shaped channel is designed and verified. As a result of field strengthening particularly nearby the contact regions, the sensitivity parameter γDark=–0.84 is obtained. Hence, the device tends to have a wider dynamic range compared with the previous Pi-shaped and planar structures [1, 2]. The TFT is very sensitive to the light of 550 nm and, making it a sound promise for low-dose indirect-conversion X-ray imaging.