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The Raman spectroscopic analysis of several stone samples with applied red pigments obtained from an archaeological excavation of an Augustinian friary discovered during the construction of an extension to Hull Magistrates Court in 1994 has revealed a surprising diversity of composition. Cinnabar, red lead and haematite have all been identified alone or in admixture; the cinnabar is exceptional in that it has only been found heavily adulterated with red ochre and red lead, as the other two pigments are found alone. There are signatures of limewash putty, which has been applied to the stone substrate prior to the painting, which is characteristic of the Roman method of wall painting, and there are no traces of gypsum found in the specimens studied. This evidence indicates an early mediaeval method of stone decoration.

The surface leakage in InAs/GaSb type-II superlattice (T2SL) is studied experimentally and theoretically for photodiodes with small sizes down to 10 × 10  μm2. The dependence of dark current density on mesa size is studied at 110 and 200 K, and surface leakage is shown to impact both generation–recombination (GR) and diffusion dark current mechanisms. A quasi-3-dimensional model to simulate the fabrication process using surface traps on the pixel's sidewall is presented and is used to accurately represent the dark current of large and small pixels with surface leakage in the different temperature regimes. The simulations confirmed that the surface leakage current has a GR and diffusion component at low and high temperature, respectively. Finally, the surface leakage current has been correlated with the change in minority carrier concentration at the surface due to the presence of donor traps.

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