GaN/InGaN heterostructures grown by ammonia MBE with a wetting metal indium layer

We have studied the influence of conditions used for the growth of InGaN layers by the molecular beam epitaxy (with ammonia as a source of nitrogen) on the properties of GaN/InGaN heterostructures. It is established tat the temperature dependence of the critical flux of indium leading to the formation of droplets for the growth of InGaN on GaN is exponential and is determined by the enhanced desorption of indium from the surface of a growing layer with increasing substrate temperature. The growth of InGaN layers on GaN, even at the maximum possible flux of indium not accompanied by the droplet formation, leads to an extended profile of indium distribution in InGaN layers. It is shown that, in order to obtain sharp heteroboundaries and increase the content of indium in thin InGaN layers, it is necessary to create and maintain the so-called "wetting" film of metallic indium on the substrate surface prior to and in the course of InGaN layer growth. Using the obtained results, basic conditions are established for growing thin InGaN layers for the active elements of light-emitting devices operating in the blue-violet spectral range.