You might not know what "lattice-matched heterojunctions" are, but if you stopped at a new stoplight, played a DVD or used a laser pointer, you've made use of technology pioneered by Jerry Woodall, distinguished professor of electrical and computer engineering at the University of California, Davis. Woodall's work, begun in the 1960s at IBM Research, is the basis for cheap, energy-efficient light-emitting diodes, or LEDs, and lasers.