From transistors to lasers and light-emitting diodes

This article is based on the 2004 Von Hippel Award address by Nick Holonyak Jr. (University of Illinois at Urbana-Champaign). Holonyak received the award for "his many contributions to research and development in the field of semiconductors, not least for the first development of semiconductor lasers in the useful visible portion of the optical spectrum" The talk was presented on Holonyaks behalf by Russell Dupuis on December 1, 2004, at the Materials Research Society Fall Meeting in Boston. With the discovery of the transistor by Bardeen and Brattain in 1947, and as a consequence of carrier injection and collection, the hole indeed became equal to the electron. The semiconductor took on new importance, as did the study of electron-hole recombination, first in the transistor materials Ge and Si, and then in III-V crystals, (e.g., GaAs and GaP). Beyond Si and its indirect-gap and heterojunction limitations, the direct- gap III-V materials, particularly III-V alloys, made possible lasers and light-emitting diodes (LEDs)-and thus optoelectronics. The direct-gap III-V alloy LED after four decades of development exceeds in performance the incandescent lamp (as well as other forms of lamps) in much of the visible range. Beyond growing display applications, it has put conventional lighting under long-range threat with a semiconductor lamp-an "ultimate lamp" that promises unusual performance and energy savings. In principle, the LED or laser, basically a p-n junction, is an ultimate lamp that cannot be exceeded.