Who Discovered the Semiconductor Transistor and How does a semiconductor turn into superconductor?

John Bardeen won his first Nobel Prize for discovering the transistor effect of semiconductor materials.

Most materials either conduct electric flow (conductors) or block that flow (insulators). But a few materials sometimes permitted some electric flow (semiconductors). Though they had been identified by the late 1800s, no one knew the value of semiconductors until Bardeen discovered the transistor effect.

The transistor has been the backbone of every computing, calculating, communicating, and logic electronics chip and circuit built in the last 50 years. The transistor revolutionized the worlds of electronics and made most of the modern pieces of essential electronic and computing hardware possible. There is no area of life or science that has not been deeply affected by this one discovery.

John Bardeen was a true child prodigy, skipping fourth, fifth, and sixth grades and receiving a master’s degree in physics at 21. With a Ph.D. from Harvard, he taught physics at the University of Minnesota until, in 1945, he was hired by Bell Laboratories, a high-tech communications and electronics research plant.

In the fall of 1947 Bardeen joined forces with William Shockley and Walter Brattain, who were already studying the possible use of semiconductor materials in electronics. Shockley shared the “industrial dream” of freeing electronics from the bulkiness, fragility, heat production, and high power consumption of the vacuum tube. To allow semiconductors to replace tubes, Shockley had to make semiconductor material both amplify and rectify electric signals. All of his attempts had failed.

Bardeen first studied and confirmed that Shockley’s mathematics were correct and that his approach was consistent with accepted theory. Shockley’s experiments should work. But the results they found using germanium, a common semiconductor, didn’t match the theory.

Bardeen guessed that unspecified surface interference on the germanium must be blocking the electric current. The three men set about testing the responses of semiconductor surfaces to light, heat, cold, liquids, and the deposit of metallic films. On wide lab benches they tried to force electric current into the germanium through liquid metals and then through soldered wire contact points. Most of November and much of December 1947 were consumed with these tests.

They found that the contact points worked, sort of. A strong current could be forced through the germanium to a metal base on the other side. But rather than amplifying a signal (making it stronger), it actually consumed energy (made it weaker).

Then Bardeen noticed something odd and unexpected. He accidentally misconnected his electrical leads, sending a micro-current to the germanium contact point. When a very weak current was trickled through from wire solder point to base, it created a “hole” in the germanium’s resistance to current flow. A weak current converted the semiconductor into a superconductor.

Bardeen had to repeatedly demonstrate the phenomenon to convince both himself and his teammates that his amazing results weren’t fluke occurrences. Time after time the results were the same with any semiconductor material they tried: high current, high resistance; low current, virtually no resistance.

Bardeen named the phenomenon “transfer resistors,” or transistors. It provided engineers with a way to both rectify a weak signal and boost it to many times its original strength. Transistors required only 1/50 the space of a vacuum tube and 1/1,000,000 the power and could outperform vacuum tubes. For this discovery, the three men shared the 1956 Nobel Prize for Physics.

The first transistor radio, the Regency TR-1, hit the market on October 18, 1954. It cost $49.95 (the equivalent of $361 in 2005 dollars.). It wasn’t until the late 1960s that transistor radios became cheap enough for everyone to afford one.