Amorphous Strontium Titanate Film as Gate Dielectric for Higher Performance and Low Voltage Operation of Transparent and Flexible Organic Field Effect Transistor

Abstract

We report that the pervoskite material, strontium titanate (STO) can be used as a gate dielectric layer of flexible and low voltage organic field effect transistor (OFET). The crystallinity, dielectric constant, and surface morphology of STO films can be controlled by the engineering of the growth condition. Under optimized growth condition, amorphous films of STO show a much better gate dielectric compared to other gate dielectrics used to date, with very small leakage current density for flexible and low voltage (<5 V) OFETs. The amorphous STO film decreases the interface trap density at organic/dielectric interface substantially. Pentacene transistors with amorphous STO gate dielectric show high mobility of 2 cm(2)/(V s), on/off ratio of 10(6), subthreshold swing of 0.3 V/dec and low interface trap density. Similarly excellent performance has been obtained in copper phthalocyanine (CuPc) based OFETs with on/off ratio ∼10(5) and carrier mobility ∼5.9 × 10(-2) cm(2)/(V s). Moreover, the operating voltage (∼5 V) has been reduced by more than one order of magnitude. It has been demonstrated that the low processing temperature of amorphous STO makes it the most suitable gate dielectric for flexible and transparent organic devices to operate under low voltage.

Biocompatible/Degradable Silk Fibroin:Poly(Vinyl Alcohol)-Blended Dielectric Layer Towards High-Performance Organic Field-Effect Transistor

“…Meanwhile, device A has a threshold voltage ( V T ) of −1 V, which is almost optimal. On the other hand, V T s of devices B and C are −11 and ~20 V, which are far from the optimal value of 0 V. It is well known that threshold voltage of OFET is strongly determined by the trap density ( N ) at the interface of dielectric and organic semiconductor of the device [ 31 ]. Low charge trap density at the dielectric/organic semiconductor interface usually benefits to low V T value.…”

Postdeposition annealing on RF-sputtered SrTiO3 thin films

“…Yadav and Ghosh recently reported that amorphous STO films can be used in transparent and flexible organic field effect transistor as a gate dielectric material. 40 They used STO thin films with a dielectric constant values in the range 10-30, and promising application in microelectronics.…”

Interface interaction of transition metal phthalocyanines with strontium titanate (100)

“…However, also interfaces between SrTiO 3 (STO) and organic molecules are studied increasingly using both experimental [ 4 – 5 ] and theoretical approaches [ 6 ]. Possible applications of STO/organic interfaces include FETs [ 7 – 8 ], photodiodes [ 9 ], and organic spin valves[ 10 ].…”