Indium incorporation processes investigated by pulsed and continuous growth of ultrathin InGaN quantum wells

•Growth processes of InGaN/GaN quantum wells with high indium content.•Interplay adlayer – desorption – incorporation – segregation are studied.•Consider indium droplet formation for indium concentration higher than 25%.•Indium droplet as indium source via adlayer.

We study the incorporation of indium into AlxGa1−xNAlxGa1−xN/GaN quantum well (QW) structures with high indium concentrations above 25% for QW thicknesses in the range 2 nm down to half a c-lattice constant under pulsed and continuous growth conditions. We want to clarify which processes limit the incorporation of indium and lead to a degrading layer structure. The data are discussed in the context of the adlayer proposed by theory (Northrup et al., 2000) [1]. The interplay of the adlayer with the incoming flux, the high desorption rate and segregation of indium can consistently explain the various observed phenomena.