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°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 75dots∕in. resolution over 180×180pixels and with sensitivity of 1.2pW∕cm2.