Thin-film transistor

About: Thin-film transistor is a research topic. Over the lifetime, 48425 publications have been published within this topic receiving 680879 citations. The topic is also known as: TFT.

Contact resistance in organic transistors that use source and drain electrodes formed by soft contact lamination

Abstract: Soft contact lamination of source/drain electrodes supported by gold-coated high-resolution rubber stamps against organic semiconductor films can yield high-performance organic transistors. This article presents a detailed study of the electrical properties of these devices, with an emphasis on the nature of the laminated contacts with the p- and n-type semiconductors pentacene and copper hexadecafluorophthalocyanine, respectively. The analysis uses models developed for characterizing amorphous silicon transistors. The results demonstrate that the parasitic resistances related to the laminated contacts and their coupling to the transistor channel are considerably lower than those associated with conventional contacts formed by evaporation of gold electrodes directly on top of the organic semiconductors. These and other attractive features of transistors built by soft contact lamination suggest that they may be important for basic and applied studies in plastic electronics and nanoelectronic systems based ...

Multi-parameter gas sensors based on organic thin-film-transistors

Abstract: In this communication, evidence is provided that an organic thin-film-transistor (OTFT) can be used as a novel gas sensor. When exposed to chemical species at room temperature, four parameters can be measured: the bulk conductivity of the organic thin film, the field-induced conductivity, the transistor threshold voltage and the field effect mobility. Measurements of these parameters may allow for recognition of molecular species.

Low-voltage, 30 nm channel length, organic transistors with a self-assembled monolayer as gate insulating films

Abstract: We made nanometer-scale (gate length of 30 nm) organic thin-film transistors using a self-assembled monolayer (2 nm thick) as a gate insulator. The fabrication steps combine electron-beam lithography and lift-off techniques for the deposition of both metal electrodes and organic semiconductors with a chemical approach (self-assembly of organic molecules) to fabricate the gate insulator. Good performances of these transistors (with a record subthreshold slop of 350 mV/decade and a cutoff frequency of 20 kHz) and low-voltage operation (<2 V) are demonstrated down to a gate length of 200 nm. A gate voltage modulation of the source-to-drain tunnel current is demonstrated for the 30 nm gate length device.

HfO2 and Al2O3 gate dielectrics on GaAs grown by atomic layer deposition

Abstract: High-performance metal-oxide-semiconductor field effect transistors (MOSFETs) on III–V semiconductors have long proven elusive. High-permittivity (high-κ) gate dielectrics may enable their fabrication. We have studied hafnium oxide and aluminum oxide grown on gallium arsenide by atomic layer deposition. As-deposited films are continuous and predominantly amorphous. A native oxide remains intact underneath HfO2 during growth, while thinning occurs during Al2O3 deposition. Hydrofluoric acid etching prior to growth minimizes the final interlayer thickness. Thermal treatments at ∼600°C decompose arsenic oxides and remove interfacial oxygen. These observations explain the improved electrical quality and increased gate stack capacitance after thermal treatments.

Towards See-Through Displays: Fully Transparent Thin-Film Transistors Driving Transparent Organic Light-Emitting Diodes**

Abstract: Fully transparent computer displays have, until now, been the vision of science-fiction movies. Nevertheless, there are numerous applications for these devices ranging, for example, from head-mounted displays to their integration in automotive windshields. In this paper we demonstrate that this vision is on the verge of becoming reality. The realization of entirely transparent displays requires both transparent light-emitting devices, in our case organic light-emitting diodes (OLEDs) with transparent contacts, and a driving scheme based on transparent thin-film transistors (TTFTs). Since the early reports on electroluminescence from multilayer, thin-film devices composed of vacuum-sublimed small organic molecules [1] and spin-coated conjugated polymers, [2] substantial research has been devoted to the improvement of device efficiencies, color purity, and lifetime. Incitement of this development is the potential use of OLEDs in future commercial flat-panel displays. OLEDs usually consist of a layer sequence of organic functional materials (charge transporters/blockers/emitters) with an overall thickness of the order of 100 nm. Most of these materials absorb light in the deep-blue or ultraviolet spectral region and are nearly transparent in the visible part of the spectrum. Organic layers applied to emit visible light are often based on so-called guest–host systems, in which a wide-bandgap host material (absorbing in the UVonly) is doped with a few weight percent of a light-emitting dye. [3] As a result, the emitting layer appears transparent. Transparent conductive oxides, most prominently indium tin oxide (ITO) and aluminum-doped ZnO (AZO), may be used as electrical contacts to OLEDs. Therefore, OLEDs seem to be promising devices for the realization of entirely transparent visible-light emitters. [4–6] OLED displays driven in passive-matrix mode are based on conventional bottom-emitting OLEDs and are considered as an approach to fabricate small-sized, low-information-content displays with moderate pixel counts. To accomplish largerarea, high-resolution OLED displays an active-matrix-addressing scheme has been suggested. [7] Conventional a-Si:H or poly-Si TFT backplanes are not suitable as drivers for transparent displays because they are opaque in the visible part of the spectrum. Putting pixels and transistors next to each other would compromise the displays’ fill factor. Organic field-effect transistors (OFETs) as pixel drivers for OLEDs have been discussed by Sirringhaus et al. [8] Transparent OFETs have also been reported. [9] However, their performance is still poor; transparent active pixels using OFETs have not yet been demonstrated. Therefore, in this paper we focus on the production of TTFTs based on the wide-bandgap oxide semiconductor zinc tin oxide (ZnO)x(SnO2)1–x ,a s a viable alternative to previously fabricated devices. Recently, research on TTFTs with channels made from ox