Walter Brattain, John Bardeen, and William Shockley were awarded the 1956 Nobel Prize in Physics for the invention of the transistor. After inventing the transistor, Brattain and Bardeen continued in basic research, Bardeen concentrating on the area of superconductivity, which is the complete absence of resistance to electric current in some materials at low temperatures. In 1972 he was awarded a second Nobel Prize in Physics for his work in superconductivity, the first person ever to receive two Nobel Physics prizes. Shockley left Bell and founded Shockley Semiconductor near Palo Alto, California, the first semiconductor firm in the area that eventually became known as Silicon Valley.