Date of Award
Bachelor of Science Honours
School of Engineering
Faculty of Computing, Health and Science
Dr Grahem Wild
A photonic power system using a silicon or germanium based device as a photonic power converter was proposed. The properties of each device were investigated to determine the optimum structure, design, configuration and efficiency for power conversion. These included, but were not limited to, device geometry, doping concentration and the wavelength of the incident beam. Relevant inferences were made from the results obtained and compared to previous work. Currently, research into photovoltaic power converters is focused on the efficiencies of complex heterostuctures made from gallium-arsenide compounds. Here, the properties of a silicon device were investigated in detail as the predicted efficiency under monochromatic light is comparatively high, much more than solar generated power, which will therefore reduce the cost of optically powered systems. The results show that an optimised silicon based photovoltaic micro-cell can produce optical to electrical power conversion as high as 43% under illumination of 980nm light. We have shown that the wavelength of the incident light determines the depth of the optimised device. The peak doping concentrations of the emitter and base regions should be as high as lx1020cm-3 and 3x1017cm-3, respectively, for maximum power conversion efficiency. The results also show that germanium-based homojunction cells can produce power conversion efficiencies as high as 36% when illuminated by 1550nm light. The validity of a completely optical network is discussed, as experiments with multiple sources propagating along a single optical fibre have been performed. Three separate signals, one for communication, one for sensing and one for power generation, can utilise the same optical fibre will no significant loss to information or power. This research is the basis for a more comprehensive study of the highest attainable efficiency of a silicon photovoltaic power converter under illumination of monochromatic light and the feasibility of a completely photonic network.
Allwood, G. (2010). Near infrared photovoltaic micro-cell for optical fibre based power harvesting. Retrieved from http://ro.ecu.edu.au/theses_hons/1359