Low-temperature characteristics of a-Si:H thin-film transistor under mechanical strain

The electrical characteristics of hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) fabricated on stainless steel foil substrates with uniaxial outward bending, were investigated at low temperatures. Temperatures ranging from 77 K to 300 K were applied, with experimental results showing the degradation of on-state current and threshold voltage at low temperatures. Compared with the flat situation, the mobility of tensile strained a-Si:H TFTs decreased at temperatures above 150 K, but remained almost the same at temperatures below 150 K. This is because outward bending will induce increase of band tail states, affecting the transport mechanism differently at different temperatures.