Dielectric ceramics/TiO 2 /single-crystalline silicon nanomembrane heterostructure for high performance flexible thin-film transistors on plastic substrates

A dielectric ceramics/TiO /single-crystalline silicon nanomembrane (SiNM) heterostructure is designed and fabricated for high performance flexible thin-film transistors (TFTs). Both the dielectric ceramics (Nb O -Bi O -MgO) and TiO are deposited by radio frequency (RF) magnetron sputtering at room temperature, which is compatible with flexible plastic substrates. And the single-crystalline SiNM is transferred and attached to the dielectric ceramics/TiO layers to form the heterostructure. The experimental results demonstrate that the room temperature processed heterostructure has high quality because: (1) the Nb O -Bi O -MgO/TiO heterostructure has a high dielectric constant (∼76.6) and low leakage current. (2) The TiO /single-crystalline SiNM structure has a relatively low interface trap density. (3) The band gap of the Nb O -Bi O -MgO/TiO heterostructure is wider than TiO , which increases the conduction band offset between Si and TiO , lowering the leakage current. Flexible TFTs have been fabricated with the Nb O -Bi O -MgO/TiO /SiNM heterostructure on plastic substrates and show a current on/off ratio over 10 , threshold voltage of ∼1.2 V, subthreshold swing ( ) as low as ∼0.2 V dec , and interface trap density of ∼10 eV cm . The results indicate that the dielectric ceramics/TiO /SiNM heterostructure has great potential for high performance TFTs.