The invention of the transistor inspired research in semiconductor materials other than germanium and silicon, including compound “direct-bandgap” semiconductors that could emit light. It was a student of John Bardeen’s at the University of Illinois, Nick Holonyak, Jr., that explored the alloy engineering aspects of compound semiconductors that led the first demonstration of practical visible-spectrum light emitting diode (LED) in 1962.
Since then, several compound semiconductor materials systems have been developed for LEDs, the most important of which is the (Al,Ga,In)N system which demonstrated blue-emitting LEDs for the first time, which was awarded the Nobel Prize in Physics in 2014. This unusual material system is now the backbone of the solid state lighting industry, which has transformed the display industry, and has now penetrated about 50% of the conventional (i.e., incandescent, fluorescent, discharge) lighting market with enormous savings energy consumption. This presentation will tell this story and also look to what we might expect in the future.