Semiconductor alloy lasers--1962

Following the report of high-efficiency generation and transmission of recombination radiation from Zn-diffused GaAs p-n junctions at the 1962 IRE Solid State Device Research Conference (July, Durham, NH), a many-laboratory race began to construct a semiconductor laser. Although it is widely believed that only GaAs was involved in the research that led to a semiconductor laser, the visible-spectrum alloy GaAs1-xPxwas in the middle of this activity and was (fall of 1962), with GaAs, a first semiconductor laser, not to mention the first laser in a semiconductor alloy or crystal that could be "tuned" in energy gap (and wavelength) from direct-gap to indirect-gap. The ternary GaAs1-xPxwas the forerunner of all present-day III-V alloys used in heterojunction devices. The sequence of events leading to the GaAs1-xPxlaser, as well as its introduction in modified form as the first practical LED, are described.