But firstly, what even are they?
Semiconductors are basically a class of materials that have a level of conductivity between conductors and insulators, hence the name. They form the core of most modern electronics, including transistors which are ‘powering’ the device you’re looking at this article on.
How did they arise?
This is another interesting story that came from a book called The Disappearing Spoon which I recommended you read in a previous post. The modern semiconductor based electronics arose in 1945 at Bell Labs in the US. A man named William Shockley was trying to build a silicon amplifier to replace the vacuum tube in computers. Vacuum tubes were fragile, hard to work with and prone to overheating. Even though the vacuum tubes were incredibly annoying, engineers needed them in computers because nothing else could do the double job of amplifying weak electronic signals, and acted as a diode, a one way valve for electricity to pass through.
Shockley knew that semiconductors were the way forward, but after 2 years of work, frustrated, he dumped the project onto two younger scientists, John Bardeen and Walter Brattain. Bardeen and Brattain were best friends and a perfect match, Bardeen was the brains and Brattain was the hands of the joint. They immediately decided that Silicon was far to brittle and hard to purify to make an amplifier. They finished building the world’s first solid state amplifier, from germanium, in 1947.
Shockley, who was in Paris at the time, was jealous. He quickly rushed back to Bell Labs to wedge himself into the world of transistor technology. When pictures were taken, Shockley pushed himself between Bardeen and Brattain. Later, he fired Bardeen to take over work on the transistor. Brattain later quit the job.
So, why do we have silicon and not germanium semiconductors today?
As the semiconductor industry boomed engineers kept trying to develop silicon semiconductors. Why? Even though germanium conducts electricity better than silicon, it also generates a lot of unwanted heat which caused germanium semiconductors to stall when they overheated. More importantly, silicon is the second most common element on earth behind oxygen, and is incredibly cheap.
At a semiconductor meeting that same year while scientists were discussing the unfeasibility of silicon semiconductors, a cheeky engineer from texas instruments stood up and announced to the crowd that he had one in his pocket. He gave the crowd an incredible demonstration. He took out a germanium transistor run record player and put a record in it. When it was playing he lowered it into a vat of boiling oil. As expected, the germanium transistor overheated and spluttered out. He then replaced the transistor with the silicon one from his pocket. This time when he lowered the record player into the boiling oil, the music continued playing.