R ARE -E ARTH D OPED U P -C ONVERTING P HOSPHORS FOR AN E NHANCED S ILICON S OLAR C ELL R ESPONSE Avi Shalav Centre of Excellence for Advanced Silicon Photovoltaics and Photonics University of New South Wales Sydney 2052 Australia A thesis submitted to the University of New South Wales in fulfilment of the requirements for the degree of Doctor of Philosophy February 2006