GaN quantum dots doped with Tb

Tb-doped GaN quantum dots grown by molecular beam epitaxy have been studied. These nanostructures present intense photoluminescence from intra-4f transitions of Tb3+ ions. It has been found that Tb atoms enhance the desorption process of Ga adatoms from the growing surface, leading to a reduction of the growth rate and, eventually, to an inhibition of the GaN quantum dot formation for a Tb content of about 2% at the growth temperature of 760°C. The presence of Tb inside quantum dots is suggested by intense photoluminescence in the green spectral range at room temperature from intra-4f transitions of Tb3+ ions, by contrast to the Tb-doped GaN thick layers.