MURRAY HILL, N.J, March 22 -- Bell Labs researchers have grown a single crystal of gadolinium oxide on a gallium arsenide semiconductor. Because the interface is perfectly smooth, the material could prove to be the best insulating layer yet for gallium arsenide-based metal oxide semiconductor field effect transistors (MOSFETs), which currently are not commercially viable. The researchers created the gadolinium oxide crystal by using molecular beam epitaxy to grow one molecular layer at a time on the gallium arsenide.