ABSTRACT
Traditionally, solar radiation is exploited using two different
methods, solar thermal technology using infrared (IR) radiation
and photovoltaic (PV) technology using visible and ultraviolet (UV)
radiation. In order to be cost effective, it is attractive to combine
both together in one device. In addition, if the incorporation of
phenomena such as impact ionisation and impurity PV can be
built into the same device, the performance of a solar cell can
be enhanced. With these aims in mind, a graded bandgap multi-
layer device structure has been designed and experimentally tested
with a well-researched GaAs/AlGaAs system. Design details and
experimental results are presented in chapters 6 and 7. This chapter
presents the experimental evidence observed for the impurity PV
effect expected from these device structures.
