Quantum-dot Cellular Automata (QCA) is a new paradigm for computation that utilizes polarization states instead of using current switching. It is being studied because of the realization of the quickly approaching limitation of the current CMOS technology. The location of two excess electrons located within four or five quantum dots on a particular cell can transmit the binary information. These dots are located in the corner of a square cell, and if there is a fifth dot it is located in the center. The electrons are allowed to tunnel freely among the dots, but are restricted from tunneling between neighboring cells. Because of the interaction between the electrons, they will anti-align within the cell giving one of two particular configurations. This configuration can be transmitted to neighboring cells. In other words, data is flowing.We present a numerical study of the fabrication defect's influence on Quantum-dot Cellular Automata (QCA) operation. The statistical model that has been introduced simulates the random distribution of positional defects of the dots within cells and of cells within arrays. Missing dots within a QCA cell structure have also been studied.We have studied specific non-clocked QCA devices using the Inter-cellular Hartree Approximation, for different temperatures. Parameters such as success rate and breakdown displacement factor were defined and calculated numerically. Results show the thermal dependence of the breakdown displacement factor of the QCA devices. It has been shown, that the breakdown displacement factor decreases with increasing temperature. As expected, multiple defects within the same QCA array have shown a reduction in success rate greater than that of a single defect influencing the system. / Department of Physics and Astronomy
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/187943 |
| Date | January 2005 |
| Creators | Barclay, Travis J. |
| Contributors | Khatun, Mahfuza |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | ix, 68 leaves : ill. (some col.) ; 28 cm. |
| Source | Virtual Press |
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