Improving the performances of oxide phototransistors using a mechanochemically treated porous visible-light absorption layer

ACS Appl. Mater. Interfaces

Park

Min

et al. 2021

Self Cite

We introduced an organic interlayer into the Schottky contact interface to control the contact property. After inserting an 11-nm-thick polyethylenimine (PEI) interlayer between the aluminum (Al) source/drain electrode and the cuprous oxide (Cu2O) channel layer, the Cu2O thin-film transistors (TFTs) exhibited improved electrical characteristics compared with Cu2O TFTs without a PEI interlayer; the field-effect mobility improved from 0.02 to 0.12 cm2/V s, the subthreshold swing decreased from 14.82 to 7.34 V/dec, and the on/off current ratio increased from 2.43 × 102 to 1.47 × 103, respectively. Careful investigation of the contact interface between the source/drain electrode and the channel layer established that the performance improvements were caused by the formation of electric dipoles in the PEI interlayer. These electric dipoles reduced the Schottky barrier height by neutralizing the charges at the metal/oxide semiconductor interface, and the holes passed the reduced Schottky barrier by means of tunneling or thermionic injection. In this way, p-type oxide TFTs, which generally need a noble metal having a high work function as an electrode, were demonstrated with a low-work-function metal. As a basic application for logic circuits, a complementary inverter based on n-type indium–gallium–zinc oxide and p-type Cu2O TFTs was fabricated using only Al source/drain electrodes. This research achieved advances in low-cost circuit design by broadening the electrode metals available for the manufacture of p-type oxide semiconductor-based electronics.

Section: Introductionmentioning

confidence: 99%

Modulation of the Al/Cu₂O Schottky Barrier Height for p-Type Oxide TFTs Using a Polyethylenimine Interlayer

ACS Appl. Mater. Interfaces

Park

Min

et al. 2021

Self Cite

ACS Appl. Mater. Interfaces

“…In the era of Internet of Things (IoT), a multitude of sensors, communication network technologies, and logic circuits have been developed. , As IoT technology continues to advance, the everyday connectivity of internet-enabled devices has become an increasingly important feature that requires low-power-consumption sensors and network systems. , In addition to the enhanced interconnection interface, the manufacturing system should possess the flexibility to satisfy customer needs in fast-changing industries. Therefore, a low-cost and flexible manufacturing system (FMS) for multi-item small-lot-sized production of IoT devices is required. − …”

Section: Introductionmentioning

confidence: 99%

Simultaneously Defined Semiconducting Channel Layer Using Electrohydrodynamic Jet Printing of a Passivation Layer for Oxide Thin-Film Transistors

Hong

Lee

et al. 2020

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A simple fabrication method for homojunction-structured Al-doped indium–tin oxide (ITO) thin-film transistors (TFTs) using an electrohydrodynamic (EHD) jet-printed Al2O3 passivation layer with specific line (W Al2O3 ) is proposed. After EHD jet printing, the specific region of the ITO film below the Al2O3 passivation layer changes from a conducting electrode to a semiconducting channel layer simultaneously upon the formation of the passivation layer during thermal annealing. The channel length of the fabricated TFTs is defined by W Al2O3 , which can be easily changed with varying EHD jet printing conditions, i.e., no need of replacing the mask for varying patterns. Accordingly, the drain current and resistance of the fabricated TFTs can be modified by varying the W Al2O3 . Using the proposed method, a transparent n-type metal–oxide–semiconductor (NMOS) inverter with an enhancement load can be fabricated; the effective resistance of load and drive TFTs is easily tuned by varying the processing conditions using this simple method. The fabricated NMOS inverter exhibits an output voltage gain of 7.13 with a supply voltage of 10 V. Thus, the proposed approach is promising as a low-cost and flexible manufacturing system for multi-item small-lot-sized production of Internet of Things devices.

“…Unlike traditional semiconductor processing, low-temperature solution processes enable the deposition of metal oxides on a broader range of substrate materials (e.g., polyimide) and provide opportunities to produce flexible devices 1 – 3 . Since the first report of InGaZnO-based thin-film transistors (TFTs), solution-processed amorphous metal oxides have been regarded as some of the most promising materials for next-generation displays because of their high mobility and transparency 4 – 6 .…”

Section: Introductionmentioning

confidence: 99%

Enhancement of electrical characteristics and stability of self-patterned In–Zn–O thin-film transistors based on photosensitive precursors

Jung

2020

Sci Rep

Self Cite

We report a novel self-patterning method for solution-processed indium zinc oxide (IZO) thin films based on photosensitive precursors. This approach is an alternative and evolutionary approach to the traditional photoresist patterning techniques. Chelate bonds between metal ions and β-diketone compounds in ultraviolet light-exposed IZO solutions provided intrinsic photosensitivity, which resulted in a solubility difference between exposed and non-exposed regions. This difference enabled self-patterning of the IZO for thin-film transistor (TFT) fabrication. Compared with previously reported self-patterning methods based on photosensitive activators, our self-patterned IZO TFTs based on photosensitive precursors displayed excellent electrical characteristics and stability. The field-effect mobility increased from 0.27 to 0.99 cm2/Vs, the subthreshold swing decreased from 0.54 to 0.46 V/dec, and the threshold voltage shift under a positive bias stress test (1,000 s) improved from 9.32 to 1.68 V. The photosensitive precursor played a key role in these improvements permitting fewer organic species which act as defect sites after metal oxide formation. Consequently, our approach compares favorably with that of conventional fabrication process using photoresist in terms of its simplicity, cost efficiency, and electrical performance.