Substrate star: Venkatraman Gopalan, professor of materials science and engineering and physics, in his optical lab. (Courtesy: Seana Wood/Penn State Materials Research Institute) The substrates on which semiconductor chip are grown usually get ignored, but they may be more important than we think. This is the finding of researchers in the US and Germany, who used high-energy X-rays to study titanium dioxide – a common substrate for insulator-to-metal semiconductors. The discovery that this mate...