Low temperature a-Si:H photodiodes and flexible image sensor arrays patterned by digital lithography

Hydrogenated amorphous silicon-based image sensor arrays were fabricated on polyethylene naphthalate substrates, with photodiodes optimized for process temperatures of $150°\mathrm{C}$ . An optimal $i$ -layer thickness was determined to minimize carrier recombination and to maintain sufficient light absorption and acceptable leakage current. Patterning of the thin-film transistor backplane was accomplished using ink-jet printed etch masks. A flexible image sensor is demonstrated with $75\text{dots}∕\mathrm{in.}$ resolution over $180\times 180\text{pixels}$ and with sensitivity of $1.2\mathrm{pW}∕{\mathrm{cm}}^2$ .