The present invention relates to an amorphous oxide and a thin film transistor using the amorphous oxide. In particular, the present invention provides an amorphous oxide having an electron carrier concentration less than 10 18 /cm 3 , and a thin film transistor using such an amorphous oxide. In a thin film transistor having a source electrode 6 , a drain electrode 5 , a gate electrode 4 , a gate insulating film 3 , and a channel layer 2 , an amorphous oxide having an electron carrier concentration less than 10 18 /cm 3 is used in the channel layer 2.

Amorphous oxide and thin film transistor

A semiconductor device can include a channel including a first binary oxide and a second binary oxide.

Combined binary oxide semiconductor device

The large surface area of ZnO nanorods makes them attractive for gas and chemical sensing, and the ability to control their nucleation sites makes them candidates for micro-lasers or memory arrays. In addition, they might be doped with transition metal (TM) ions to make spin-polarized light sources. To date, most of the work on ZnO nanostructures has focused on the synthesis methods and there have been only a few reports of the electrical characteristics. We review fabrication methods for obtaining device functionality from single ZnO nanorods. A key aspect is the use of sonication to facilitate transfer of the nanorods from the initial substrate on which they are grown to another substrate for device fabrication. Examples of devices fabricated using this method are briefly described, including metal-oxide semiconductor field effect depletion-mode transistors with good saturation behavior, a threshold voltage of ∼−3 V and a maximum transconductance of order 0.3 mS/mm and Pt Schottky diodes with excellent ideality factors of 1.1 at 25 °C and very low (1.5 × 10 −10  A, equivalent to 2.35 A cm −2 , at −10 V) reverse currents. The photoresponse showed only a minor component with long decay times (tens of seconds) thought to originate from surface states. These results show the ability to manipulate the electron transport in nanoscale ZnO devices.

ZnO nanowire growth and devices

Flexible-electronics is rapidly finding many main-stream applications where low-cost, ruggedness, light weight, unconventional form factors and ease of manufacturability are just some of the important advantages over their conventional rigid-substrate counterparts. Flexible Electronics: Materials and Applications surveys the materials systems and processes that are used to fabricate devices that can be employed in a wide variety of applications, including flexible flat-panel displays, medical image sensors, photovoltaics, and electronic paper. Materials discussed range from polymeric semiconductors to nanotube transparent conductors, highlighting the important characteristics of each system and their target applications. An overview of the performance benchmarks for the different materials is given in order to allow a direct comparison of these different technologies. Furthermore, the devices and processes most suitable for given applications in flexible electronics are identified. Topics covered include: An overview and history of flexible electronics Novel materials for solution-processable thin-film electronic devices and their properties Low-temperature processing of conventional materials and devices on plastic foils Novel techniques, such as printing and roll-to-roll processing, for large-area flexible electronics manufacturing Materials and device physics relevant to flexible electronics Device integration on flexible substrates Mechanical and electronic characteristics for thin-film transistors and nano-scale transparent conductors on flexible platforms Applications towards flexible displays, sensors, actuators, solar energy, radio-frequency identification, and micro-electro-mechanical systems Written by leading researchers in the field, Flexible Electronics: Materials and Applications serves as a reference for researchers, engineers, and students interested in the characteristics, capabilities, and limitations of these exciting materials and emerging applications.

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Flexible Electronics: Materials and Applications

Recent advances in ZnO transparent thin film transistors

In flexible electronics, plastic substrates can limit processing temperatures to less than 100° C. Consequently, most semiconductors, including amorphous silicon, may be incompatible with temperature-sensitive plastic substrates. While organic semiconductors may seem well suited to this particular application niche, their stability is questionable and their mobility is often low (∼0.1 cm2/V-s). In this paper we show that ZnO is a promising semiconductor candidate for flexible electronics, because thin film transistors can be fabricated at room temperature with higher mobility (> 1 cm2/V-s) and high on/off ratio (> 104).

S. Agrawal

Papers

ZnO Thin Film Transistors for Flexible Electronics

Effect of ambient gas on grain growth of CZTS layer: study on device efficiency