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.
Dmitri Z. Garbuzov
The 1970 demonstration of the first room-temperature diode laser crowned years of scientific and technological research developments involving optical semiconductors. These accomplishments parallel, but lag, the microelectronics revolution that started with the transistor, first demonstrated in 1947 (leading to the displacement of vacuum tube electronics in the marketplace). Although the laser had already been invented by Charles Hard Townes and Arthur Leonard Schawlow, separately by Gordon Gould, and separately in the Soviet Union by Aleksandr Prokhorov, there was no practical laser "chip" which would make the laser a commodity, one that today is displacing more inefficient lasers (those based on gas discharge or flashlamp designs) in the consumer, industrial, medical, and government marketplaces.