High performance electric-double-layer amorphous IGZO thin-film transistors gated with hydrated bovine serum albumin protein

• A typical a-IGZO TFT with hydrated BSA as the gate dielectric exhibits a field-effect mobility (113.5 cm2 V−1 s−1) and a threshold voltage (0.25 V).
• The excellent device performance can be attributed to the formation of electric double-layers near the interfaces of hydrated BSA.

Device performance of amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) has been improved greatly by using bovine serum albumin (BSA) as the top gate dielectric. BSA is a natural protein with acidic and basic amino acid residues, which is easily hydrated in air ambient. A typical a-IGZO TFT with hydrated BSA as the top gate dielectric exhibits a field-effect mobility (μFE) value of 113.5 cm2 V−1 s−1 in saturation regime and a threshold voltage (VTH) value of 0.25 V in air ambient. The excellent device performance can be well explained by the formation of electric double layers (EDLs) near the interfaces of a-IGZO/hydrated BSA and hydrated BSA/gate electrode. The reliability issue of a-IGZO TFTs gated with hydrated BSA has been also investigated by using the life time test without encapsulation. The VTH value increases and μFE,sat value reduces slightly for the a-IGZO TFT and remain stabilized over 60 days.

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