John Bardeen and the Point‐Contact Transistor

To this day it is not well understood that the bipolar transistor began with John Bardeen and Walter H. Brattain's point‐contact transistor. The invention of the point‐contact transistor was a momentous event, not only in itself but even more because of the unimaginable revolution in electronics that followed. This revolution, which continues unabated, had a beginning: Bardeen's recognition of minority‐carrier injection—that is, his realization that an applied voltage causes valence band holes from the surface region of an n‐type semiconductor material near a metal contact to be injected into the bulk of the material. This realization made the semiconductor suddenly important and no longer just an interesting material to study.