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Zinc Oxide (ZnO) is a promising semiconductor material for future transistors and when grown as nanowires, is an exciting prospect for high-performance nanowire field effect transistors (NWFETs). To understand the performance limits of the material and the nanowire device structure, this thesis analyzes the electrical characteristics of ZnO NWFETs through the use of a three-dimensional simulator of NWFETs with multiple gates, NanowireMG, developed by Mincheol Shin at the Information and Communications University in Korea and provided courtesy of nanoHUB, a web-based resource by Purdue University. Chapter 2 examines ZnO and its important physical and electrical properties along with various methods of nanowire growth. This is followed by a description of the software in Chapter 3 which examines the numerical techniques used in the simulations and provides results for a simulation example of a Si NWFET using the software. In Chapter 4, we describe various experimental studies performed by different groups on ZnO NWFETs and present their results. Chapter 5 includes the results of simulations performed by varying different aspects of the device, including gate configuration (single- to quad- gate), channel length, nanowire diameter, dielectric constant, aspect ratio (channel length/width) and temperature. A comparison is then drawn between the results obtained by Mincheol Shin [1-3] for Si NWFETs using the same software tool and our simulation results for ZnO NWFETs. This thesis concludes by summarizing the important results acquired from the simulations and charting a course of action to enhance device performance for future work. |
