Influence of hydrogen pre-growth flow on indium incorporation into InGaN layers

In metalorganic vapour phase epitaxy (MOVPE) hydrogen is not commonly used in the carrier gas during growth of InGaN layers since it interferes with indium incorporation. However, hydrogen leads to a smoother surface morphology of the growing layers which is beneficial in many optoelectronic devices. The influence of hydrogen on indium incorporation was studied here. This study concludes that hydrogen alters the state of the GaN surface to the one, that does not favor indium incorporation. However, this change of the surface state by hydrogen is not immediate but occurs during the exposition of the GaN surface to H2 flow and leading to a significant In-content gradient in the InGaN layer grown with 1% (of total flow) of hydrogen in the carrier gas. We showed, that indium content on the GaN/InGaN interface is different in the case, when hydrogen is present or absent during pre-growth vent. For the InGaN sample grown without hydrogen in the carrier gas, In-content gradient was not observed.