No description available.

The metallic single electron transistor (SET) has been shown to provide charge sensitivity on the order of 10-6 e/(Hz)1/2, when operated as a charge amplifier. This makes it an ideal candidate for low-noise measurement schemes, such as monitoring nano-mechanical oscillations, or reading out the charge state of a quantum bit. The SET operates by exploiting quantum tunneling across an ‘island’ between two insulating tunnel junctions, and can be modulated by a capacitively coupled gate electrode. A metallic SET has been fabricated and characterized at low frequencies. The device was fabricated on a silicon substrate coated with a bi-layer resist, using electron beam lithography. The Al-AlOx¬-Al tunnel junctions were created using double angle evaporation. Samples were tested near 300 mK in a custom helium-3 cryostat system. Results which characterize the SET parameters and conductance behaviour were obtained, in both the superconducting and normal states. This thesis contains a discussion of the fabrication procedures and dc measurement techniques required to produce and test a single electron transistor. Relevant background theory relating to SET operation and cryogenic laboratory techniques is presented. A brief discussion of proposed future experiments using a dual gate radio frequency SET as a more sensitive amplifier is introduced. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-08-01 14:07:55.427

Zinc oxide is a familiar ingredient in common household items including sunscreen and medicines. It is, however, also a semiconductor material. As such, it is possible to use zinc oxide (ZnO) to make semiconductor devices such as diodes and transistors. Being transparent to visible light in its crystalline form means that it has the potential to be the starting material for so-called 'transparent electronics', where the entire device is transparent. Transparent transistors have the potential to improve the performance of the electronics currently used in LCD display screens. Most common semiconductor devices require the material to be selectively doped with specific impurities that can make the material into one of two electronically distinct types – p- or n-type. Unfortunately, making reliable p-type ZnO has been elusive to date, despite considerable efforts worldwide. This lack of p-type material has hindered development of transistors based on this material. One alternative is a Schottky junction, which can be used as the active element in a type of transistor known as a metal-semiconductor field effect transistor, MESFET. Schottky junctions are traditionally made from noble metal layers deposited onto semiconductors. Recent work at the Canterbury University has shown that partially oxidised metals may in fact be a better choice, at least to zinc oxide. This thesis describes the development of a fabrication process for metal-semiconductor field effect transistors using a silver oxide gate on epitaxially grown zinc oxide single crystals. Devices were successfully produced and electrically characterised. The measurements show that the technology has significant potential.

No description available.

The basis of a novel bipolar transistor structure was proposed by Dr R. Aubusson of Middlesex Polytechnic in 1977. The novelty lies in replacing the conventional overlay transistor's P+ base grid with a refractory metal grid, in order (a) to lower the base resistance and (b) to autoregister the emitter. It was claimed that the linearity of the transistor would also be improved. A number of questions raised by this idea have been investigated, the methods and conclusions of which are presented here. Plausible structures, using the metal base grid, are proposed and compared with conventional structures. Some advantages are seen to be possible. The current understanding of distortion analysis applied to transistors is reviewed. The main ideas are presented in a unified manner and are extended to higher order. A number of the transistor's second order effects are analysed in a novel fashion. The metal base grid transistor is analysed and compared with conventional transistors, with favourable results. Practical aspects of fabricating the metal base grid transistor were investigated. A procedure for deposition has been determined and is presented here along with the film physical and electrical characteristics. Analysis of the tungsten-silicon interface shows the suitability of the metallization as a base grid. Suitable means of delineating the tungsten film have been assessed and a working procedure determined. Subsequent deposition of various insulators has been investigated and the problems associated with the readily oxidized tungsten film have been overcome. Formation of the emitter, requiring further high temperature processing, has been assessed in view of the limitations imposed by the preformed base metallization. In summary, it has been shown that the novel structure can be constructed and that significant performance improvement is to be expected, although a full realization was not possible within the resource constraints of the project.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 92).

Thesis (M.S.)--University of Wisconsin--Madison, 1971. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The purpose of this investigation was to determine the parameters of emitter drift and to suggest a mechanism for this phenomenon.

No description available.