Formation of micro-crystals on the (100) surface of SrTiO3 at elevated temperatures

Droplet-like features and regularly shaped micro-crystals appear on the (100) surface of single-crystals of stoichiometric and doped SrTiO3 as a result of heat treatment around 1000–1100°C under ambient pressure. Secondary ion mass spectrometry, atomic force microscopy and X-ray photoemission are employed to characterize the morphology of the modified surface. The results provide evidence of an accumulation of SrOx on the surface in a liquid form and subsequent recrystallization as SrO on prolonged annealing. The phenomena are discussed in relation to the restructuring in the near-surface region and the loss of material at the temperatures employed, as evident from thermogravimetrical measurements.