A thin film transistor (TFT) includes a source electrode, a drain electrode, and a gate electrode. A gate insulator is coupled to the source electrode, drain electrode, and gate electrode. The gate insulator includes room temperature deposited high-K materials so as to allow said thin film transistor to operate at low operating voltage.

Low voltage flexible organic/transparent transistor for selective gas sensing, photodetecting and CMOS device applications

Several hundred thousands of tons of ZnO are used by per year, e.g. as an additive to concrete or to rubber. In the field of optoelectronics, ZnO holds promises as a material for a blue/UV optoelectronics, alternatively to GaN, as a cheap, transparent, conducting oxide, as a material for electronic circuits, which are transparent in the visible or for semiconductor spintronics. The main problem is presently, however, a high, reproducible and stable p-doping. We review in this contribution partly critically the material growth, fundamental properties of ZnO and of ZnO-based nanostructures, doping as well as present and future applications, with emphasis on the electronic and optical properties including stimulated emission. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

ZnO : From basics towards applications

ZnO is presently experiencing a research boom with more than 2000 ZnO-related publications in 2005. This phenomenon is triggered, for example, by hope to use ZnO as a material for blue/UV optoelectronics as an alternative to GaN, as a cheap, transparent, conducting oxide, as a material for electronic circuits that are transparent in the visible or for semiconductor spintronics. Currently, however, the main problem is to achieve high, reproducible and stable p-doping. Herein, we critically review aspects of the material growth, fundamental properties of ZnO and ZnO-based nanostructures and doping as well as present and future applications with emphasis on the electronic and optical properties including stimulated emission.

ZnO: Material, Physics and Applications

1D metal-oxide nanostructures have attracted much attention because metal oxides are the most fascinating functional materials. The 1D morphologies can easily enhance the unique properties of the metal-oxide nanostructures, which make them suitable for a wide variety of applications, including gas sensors, electrochromic devices, light-emitting diodes, field emitters, supercapacitors, nanoelectronics, and nanogenerators. Therefore, much effort has been made to synthesize and characterize 1D metal-oxide nanostructures in the forms of nanorods, nanowires, nanotubes, nanobelts, etc. Various physical and chemical deposition techniques and growth mechanisms are exploited and developed to control the morphology, identical shape, uniform size, perfect crystalline structure, defects, and homogenous stoichiometry of the 1D metal-oxide nanostructures. Here a comprehensive review of recent developments in novel synthesis, exceptional characteristics, and prominent applications of one-dimensional nanostructures of tungsten oxides, molybdenum oxides, tantalum oxides, vanadium oxides, niobium oxides, titanium oxides, nickel oxides, zinc oxides, bismuth oxides, and tin oxides is provided.

One-Dimensional Metal-Oxide Nanostructures: Recent Developments in Synthesis, Characterization, and Applications

ZnO is an attractive material for applications in electronics, photonics, acoustics, and sensing In optical emitters, its high exciton binding energy (60 meV) gives ZnO an edge over other semiconductors such as GaN if reproducible and reliable p-type doping in ZnO were to be achieved, which currently remains to be the main obstacle for realization of bipolar devices On the electronic side, ZnO holds some potential in transparent thin film transistors (TFTs) owing to its high optical transmittivity and high conductivity Among the other promising areas of application for ZnO are acoustic wave devices, due to large electromechanical coupling in ZnO, and devices utilizing nanowires/nanorods such as biosensors and gas sensors and solar cells, since it is relatively easy to produce such forms of ZnO nanostructures, which have good charge carrier transport properties and high crystalline quality Despite the significant progress made, there is still a number of important issues that need to be resolved before ZnO can be transitioned to commercial use, not to mention the stiff competition it is facing with GaN, which is much more mature in terms of devices In this paper, recent progress in device applications of ZnO is discussed and a review of critical issues for realization of ZnO-based devices is given

https://doc.rero.ch/record/21182/files/_zg_r_mit_-_ZnO_Devices_and_Applications_A_Review_of_Current_20101229.pdf

ZnO Devices and Applications: A Review of Current Status and Future Prospects

A wide-band gap oxide alloy, BeZnO, is proposed and studied in this letter The BeZnO films were deposited on sapphire substrates by our hybrid beam deposition growth method The value of the energy band gap of BeZnO can be efficiently engineered to vary from the ZnO band gap (34 eV) to that of BeO (106 eV) BeZnO can be used for fabricating films and heterostructures of ZnO-based electronic and photonic devices and for other applications Changes in the measured energy band gap and lattice constant values with Be content are described for BeZnO alloys

Wide-band gap oxide alloy: BeZnO

The authors have fabricated ultraviolet (UV) laser diodes based on ZnO∕BeZnO films The devices have p-n heterojunction structures with a multiple quantum well (MQW) active layer sandwiched between guide-confinement layers The MQW active layer comprises undoped ZnO and BeZnO, while the two guide-confinement layers were As-doped p-type ZnO∕BeZnO and Ga-doped n-type BeZnO∕ZnO films, respectively The exciton binding energy in the MQW region is exceptionally large (263meV) Exciton-related lasing was observed by optically pumping the MQWs ZnO∕BeZnO-based diodes showed laser action by current injection at room temperature The lasing mechanism is inelastic exciton-exciton collision

Excitonic ultraviolet lasing in ZnO-based light emitting devices

The potential use of ZnO-based photonic and electronic devices has been demonstrated by the fabrication of prototype ultraviolet (UV) photodetector and field-effect transistor (FET) devices that contain films of p-type ZnO with arsenic as the p-type dopant. These p-type films have high crystalline quality and show long-term stability. The ZnO UV photodetectors are based on p-n junctions. The FETs are made with metal-semiconductor Schottky contacts on p-type ZnO and are normally off (enhancement) devices. The spectral and electrical characteristics of these devices are presented and explained.

C. J. Youn

Papers

Wide-band gap oxide alloy: BeZnO

Excitonic ultraviolet lasing in ZnO-based light emitting devices

ZnO devices: Photodiodes and p-type field-effect transistors