Transistor
The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Julius Edgar Lilienfeld patented a field-effect transistor in 1926 but it was not possible to actually construct a working device at that time. The first practically implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley. The transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.
Herbert Kroemer
Kroemer was elected as a member of the National Academy of Engineering in 1997 and the National Academy of Sciences in 2003. He always preferred to work on problems that are ahead of mainstream technology. In the 1950s, he invented the drift transistor and was the first to point out that advantages could be gained in various semiconductor devices by incorporating heterojunctions. Most notably, in 1963 he proposed the concept of the double-heterostructure laser, which is now a central concept in the field of semiconductor lasers. Kroemer became an early pioneer in molecular beam epitaxy, concentrating on applying the technology to untried new materials.