A common thread running through the groups work almost since its inception is the deposition of semiconductor films from solution. The two
main methods we have used are chemical bath deposition (CBD) and electrochemical deposition. Over the past few years, most of our work has
been on CBD. CBD refers to film formation from a solution (almost always aqueous) where a chemical reaction slowly occurs to form the required film.
It is thus very different from some other solution methods, such as spin coating, where the material to be deposited already is present in a liquid in a
colloidal or suspended state. Most of our recent work on CBD has been on ZnO with some also on composites and solid solutions.
We are particularly interested in factors that affect reproducibility in CBD. Several such factors that we have identified are: the beneficial effect of
low levels of certain impurities in the deposition bath; differences in the two sides of glass substrates and the effect of the nature of the vessel in which deposition
is carried out. Since ZnO can be used for nanoporous solar cells, we are particularly interested in factors that control the nature of the deposit, in
particular the morphology, porosity and feature size. In multicomponent CBD, there are many more issues than in simple compound formation: the
interactions between different components; whether the film formed is a composite or solid solution; if a composite, how are the different phases intermixed?
We are studying two types of nanoporous, semiconductor-sensitized
cells: all-solid state cells (commonly known as Extremely Thin Absorber
Techniques commonly used/skills acquired in the group
Various methods of solution deposition of semiconductor films, with
emphasis on chemical bath deposition.