Russell Ohl's specialized area of research was into the behavior of certain types of crystals.
He worked on materials research in the 1930s at AT&T's Bell Labs’ Holmdel facility, investigating diode detectors suitable for high-frequency wireless, broadcasting, and military radar.
His work was only understood by a handful of scientists in the organization, one of whom was Dr. Walter Brattain (one of the trio who invented the germanium bipolar transistor in 1947, and who would be awarded the Nobel Prize for Physics in 1956).
[2][3] At the time hardly anyone knew anything about the impurities within these crystals, but Russell Ohl discovered the mechanism by which it worked.
Ohl later found that super-purifying germanium was the key to making repeatable and usable semiconductor material for diodes.