Enhanced radiative recombination in AlGaN quantum wells grown by molecular-beam epitaxy

Dependences of the intensity of cathodoluminescence in multiple Al _0.55 Ga _0.45 N/Al _0.45 Ga _0.55 N quantum wells grown by molecular-beam epitaxy on the growth conditions are studied. An increase (by almost two orders of magnitude) in the intensity of the cathodoluminescence peak with an energy of 4.45 eV is observed as the quantum-well layer grows in the conditions of deep depletion with respect to ammonia. In this case, a tendency towards the mode of three-dimensional growth can be inferred from the pattern of diffraction of high-energy electrons; this effect is interpreted using a model of formation of AlGaN quantum dots.