High-performance transparent and flexible inorganic thin film transistors: a facile integration of graphene nanosheets and amorphous InGaZnO

Abstract

Transparent and flexible thin film transistors (TFTs) with high performance based on solution processed graphene nanosheets (GNSs)-amorphous indium-gallium-zinc-oxide (a-IGZO) composites have been developed. A high electron mobility of 23.8 cm 2 V À1 s À1 has been achieved, which is about thirty times higher than those of the pristine a-IGZO TFTs (0.82 cm 2 V À1 s À1 ) and hydrogenated amorphous silicon (<1 cm 2 V À1 s À1 ). The on/off current ratio remains in a high order of 10 6 demonstrating the sustainability of the TFT devices. In addition, transparent GNSs-a-IGZO TFTs with a Ta 2 O 5 dielectric layer show superior resistance to mechanical bending with the variation of only 8% in mobility after 100 times of repeated cyclic bending compared with the degradation of more than 70% for the pristine a-IGZO device. Our results demonstrate that GNSs not only play an important role in forming a conducting network in the active matrix, but also enhance the mechanical bending stability of GNSsa-IGZO composites. It therefore paves a key step to develop large-scale applications for next-generation transparent and flexible electronics.

Metal oxide semiconductor thin-film transistors for flexible electronics

“…229,231 Finally, flexible glass substrates have been utilized to allow high annealing temperatures (500 C) in solution-processed IGZO TFTs. 201 b. Barrier layers.…”

“…76,145,[190][191][192] 83 either in the form of neat IGZO or in blends of IGZO and graphene nanosheets. 83,200,201 B. Flexible n-type vacuum-processed TFTs…”

“…83,192,201,228 It is noticeable that with only one exception, 145 all the TFTs in group (I) use either polymeric or SiO 2 gate dielectrics, whereas all the devices in group (II) and (III) predominantly employ metal oxide gate dielectrics (e.g., Al 2 O 3 and ZrO 2 ) with high R . Due to the widespread usage of gate dielectrics with high R in groups (II) and (III), the device operational voltages are overall small, with threshold voltages 5 V. a.…”

“…Finally, another interesting improvement approach has been demonstrated by Dai et al, who proposed to utilize blends of IGZO precursor and graphene nanosheets. 201 In this study, the graphene was shown to act as a conductive filler assisting charge transport in the IGZO active layer, and thereby increasing the drain current. By keeping the graphene concentration below the percolation threshold, only the on current increases, whilst the off current is kept low.…”

Graphene-Paper Based Electrochemical Sensors

“…Besides the methods mentioned above, solution casting, spin coating, spray coating and dip coating [42][43][44][45] have also been explored for the preparation of graphene papers or films. For example, GO or rGO solution was deposited on poly(ethylene terephthalate) (PET), SiO 2 / P++Si and Au via various techniques to prepare thin films [46][47][48][49], although it is still a challenge to obtain graphene films with uniform thickness and few wrinkles by such type of approaches.…”