Infrared light that has energy significantly lower than the bang-gap of silicon is not absorbed or emitted in standard silicon solar cells. However, these photons can be absorbed and emitted by defects, such as dislocations. By using a state-of-the-art spectral PL tool with variable wavelength excitation sources, this project will explore the possibility of two-step absorption of infra-red photons through defect states, combined with novel device designs that limit the reverse processes of relaxation back through the defect states, to increase the sensitivity of solar cells in this part of the spectrum. Novel approaches to measuring two-step absorption will also be used to study the properties of the well-known D-lines emitted from dislocations in silicon.
The project will be experimentally intensive, and will include working with a laser-based confocal microscope and other optical spectroscopy equipment. It will also include detailed physical modelling of the luminescence processes. It would suit a student with a background in semiconductor engineering or physics. The project will be supervised by Prof Daniel Macdonald and Dr Hieu Nguyen at ANU, and will involve collaboration with researchers at UNSW and NREL in the US.