Patterning of perovskite thin films for electrical and optical characterisation

Abstract: While perovskite solar cells have become increasingly more efficient and popular, electrical characterisation of the semiconductor properties of perovskites has been limited due to the instability of the material. In this work, multiple approaches for creating such electrical test structures from perovskites are discussed. The chemical processing limitations for perovskites are laid out and common semiconductor processes are discussed from the viewpoint of perovskite compatibility. A partially successful spin-on patterning approach is demonstrated by combining a patterned silane-based hydrophobic layer with liquid phase perovskite deposition. Structured perovskite is successfully created with a topdown approach by lithographic patterning of a perovskite compatible resist stack and pattern transfer via ion beam etching. Photoluminescence measurements are used to confirm that the perovskite remained unaffected by the patterning process. Patterning of the contact layer and successful deposition of a CuSCN transport layer using deep-UV lithography are shown. An alternative approach using electron beam lithography is discussed.