Nobel Lecture: Growth of GaN on sapphire via low-temperature deposited buffer layer and realization of $p$-type GaN by Mg doping followed by low-energy electron beam irradiation^*

This is a personal history of one of the Japanese researchers engaged in developing a method for growing GaN on a sapphire substrate, paving the way for the realization of smart television and display systems using blue LEDs. The most important work was done in the mid to late 1980s. The background to the author’s work and the process by which the technology enabling the growth of GaN and the realization of $p$-type GaN was established are reviewed.

Figure 1

Susceptor temperature sequence in the growth of GaN on a sapphire substrate using a low-temperature-deposited AlN buffer layer.

Figure 2

Scanning electron microscopic images of GaN on a sapphire (0001) substrate (a) without and (b) with a low-temperature-deposited AlN buffer layer. From [12].

Figure 3

Change in blue PL intensity upon electron beam (EB) irradiation of Zn-doped GaN. From [7].

Figure 4

Schematic drawing of the activation of hydrogen-passivated Mg in GaN ([49]) and electroluminescence pattern of a GaN LED in which only the area of the “M” was irradiated with an electron beam ([10]).

Figure 5

Image of the Earth at night provided by NASA. http://earthobservatory.nasa.gov/Features/NightLights/page3.php.