Relaxed c-plane InGaN layers for the growth of strain-reduced InGaN quantum wells

A fully relaxed In_0.1Ga_0.9N layer was grown by plasma-assisted molecular beam epitaxy on c-plane GaN using a grading technique. The growth of the graded InGaN layer in the intermediate regime enabled a smooth surface without the accumulation of In droplets. Transmission electron microscopy images show that the relaxation occurs through the formation of a high density of threading dislocations (TDs). Despite the presence of these TDs, relaxed InGaN films were then successfully used as a pseudo-substrate for the growth of InGaN/GaN quantum wells which luminesced at room temperature. (paper)