In Ohl's crystal, the crack was a P-N junction, and shining the light initiated the current across the junction. Although Brattain and Bardeen's point-contact transistor soon became obsolete, it led to a host of semiconductor devices, including the microprocessor, which can incorporate millions of transistors. Today's computers all use such microprocessors.
Brattain and Bardeen patented the invention in their names. A few weeks later, Shockley announced his invention of the sandwich transistor. Shockley's invention (patented in his name), and the junction transistor that developed from it, turned out to be easier to mass-produce than Brattain and Bardeen's point-contact transistor.
Although Brattain remained in Shockley's transistor group for a few more years, he was usually excluded from the cutting-edge research and soon transferred to another research team. Bardeen and Shockley eventually left Bell Labs, the former to join the faculty of the University of Illinois in 1951, and the latter in 1953 for a position at the California Institute of Technology. Shockley later formed his own company, Shockley Semiconductor, in Silicon Valley. Having gone their separate ways, the three men learned individually in November 1956 that they were jointly awarded that year's Nobel Prize in physics.
In 1967, following his retirement from Bell Labs, Brattain returned full-time to his alma mater, Whitman College, where already five years earlier he had begun to teach an occasional physics course for nonscience majors. Two years earlier, he had also begun to collaborate with Whitman chemistry professor David Frasco. Supported by Battelle Northwest Laboratories of Richland, Washington, Brattain and Frasco conducted investigations of phospholipid bilayers as a model for the surface of living cells.
In 1974, two years after he retired from Whitman, Brattain was elected to the National Inventors Hall of Fame. He died in Seattle, of Alzheimer's disease, at t
