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.
| Identifer | oai:union.ndltd.org:canterbury.ac.nz/oai:ir.canterbury.ac.nz:10092/3439 |
| Date | January 2009 |
| Creators | Turner, Gary Chandler |
| Publisher | University of Canterbury. Electrical and Computer Engineering |
| Source Sets | University of Canterbury |
| Language | English |
| Detected Language | English |
| Type | Electronic thesis or dissertation, Text |
| Rights | Copyright Gary Chandler Turner, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml |
| Relation | NZCU |
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