World’s first violet LED based on Mg-doped GaN.first Mg-doped GaN v iolet LED.At this time,(RCA) was still one of the premier manufacturers of color televisions, which used standard cathode ray tubes to present the images to viewers.At RCA’s central research laboratory in Princeton, NJ, James Tietjen had become the director of the Materials Research Division, and he wanted to develop a flat television that could be hung on the wall like a painting. To create a full color image, one must provide red, green, and blue pixels in the display.
Tietjen realized that he already had red LEDs available using GaAs, and now green ones had entered the scene based on GaP:N technology. Bback in 1968 he recognized that all that was needed for a flat TV based on LEDs was a bright blue LED.