High mobility flexible polymer thin-film transistors with an octadecyl-phosphonic acid treated electrochemically oxidized alumina gate insulator

Abstract

Flexible solution-processed polymer thin-film transistors (PTFTs) with a low band-gap (LBG) donoracceptor (D-A) conjugated polymer as the active layer and electrochemically oxidized alumina (AlO x :Nd) as the gate insulator are fabricated on polyethylene naphthalate (PEN) substrates. The AlO x :Nd insulator exhibits excellent insulating properties with low leakage current, a high dielectric constant and a high breakdown field. To improve the interface coupling between the polymer active layer and the AlO x :Nd insulator, the AlO x :Nd insulator is treated with octadecyl-phosphonic acid (ODPA), forming self-assembled monolayers (SAMs) on the surface, and great improvement in TFT performance with the highest mobility of 2.88 cm 2 V À1 s À1 is attained. The performance improvement is attributed to the smoother surface and lower surface energy of the ODPA-treated AlO x :Nd compared to those of bare AlO x :Nd. In addition, the flexible PTFT exhibits only small shifts in the transfer curves at bending curvatures (R) at 30 mm, but the device shows larger threshold voltage and higher off current (I off ) after bent at R = 5-20 mm, which may be attributed to the damage in the insulator-semiconductor interface.

Excellent low-voltage operating flexible ferroelectric organic transistor nonvolatile memory with a sandwiching ultrathin ferroelectric film

“…However, a relative high operating voltage was needed to switch the memory states due to the thick ferroelectric P(VDF-TrFE-CTFE) gate dielectric that was required to minimize the gate leakage current in the last a few reports 25 . Additionally, the method that employing a reasonable interfacial layer to improve the mobility and to reduce the leakage current in conventional OFETs should also be applicable to Fe-OFETs 8 , 24 , 26 . Combining two concepts of “low E C ferroelectric polymer” and “ultrathin ferroelectric film” is a desirable route to achieve a Fe-OFET NVM operating at the satisfactory low voltage, preferably ≤5 V, which has not been reported.…”

Letter : Solution-processed flexible zinc-tin oxide thin-film transistors on ultra-thin polyimide substrates

“…c) that there are Nd clusters (dark areas) segregated in the Al–Nd film. The segregated Nd is important for releasing compressive or tensile strength during bending . The dielectric properties of AlO x :Nd were assessed by fabricating MIM capacitors.…”

“…The segregated Nd is important for releasing compressive or tensile strength during bending. [21][22][23] The dielectric properties of AlO x :Nd were assessed by fabricating MIM capacitors. The capacitance density (C i ) of the AlO x : Nd film is 42.0 nF/cm 2 .…”

P‐1.10: Solution‐processed metal oxide semiconductors fabricated with oxygen radical assisting perchlorate aqueous precursors through a new low‐temperature reaction route

“…Then it was anodized to form a 200-nm layer of AlO X :Nd on the surface of it. [17][18][19][20] The dielectric properties of AlO x :Nd were assessed by fabricating MIM capacitors. The capacitance density (Ci) of the AlO x :Nd film was 37.0 nF·cm -2 .…”