about them. While scientists weren’t sure how they worked, they were certain
that semiconductors were useful. Semiconductor crystals were used in radio and
radar receivers because they could take in the high-frequency alternating signal
of the radio wave and extract the low frequencies necessary for the headphones.
Crystals which did this were known as rectifiers.
During World War II, radio and radar were extremely important — and
therefore so were rectifiers. But rectifiers had a problem known as “burn out.”
Sudden bursts of electricity in the wrong direction could destroy them. So one
of the tasks the US government gave scientists during the war was to produce
It was the Purdue University Physics lab, led by Karl Lark-Horovitz, that
managed to make them. One of the graduate students, Seymour Benzer, accidentally
discovered that a crystal of germanium — a semiconductor which was not well
understood at the time — could withstand higher voltage than any current
rectifier. Benzer spent over a year tinkering with germanium until he discovered
that mixing in trace elements of tin could produce rectifiers that were ten
times more resistant than was standard.
Most people who heard about the results wouldn’t believe it until they saw
it with their own eyes. But soon germanium was established as a crucial part of