Investigation of defect structures in InGaN/GaN multiple quantum wells grown on Si(1 1 1) substrate by metalorganic vapor phase epitaxy

Multiple quantum wells based on InGaN/GaN have been successfully grown on high-quality Si(1 1 1) substrates by metalorganic vapor phase epitaxy (MOVPE) using composite buffer layers. The V defect structures within the multiple quantum wells were investigated using a variety of techniques. By transmission electron microscopy (TEM), it was clearly observed with the buried InGaN/GaN multiple quantum wells on the sidewall {1 0 1¯ 1}. The barrier thickness was also found to increase from the bottom to the top layer on both (0 0 0 1) and {1 0 1¯ 1} facets. A decreased fill factor based on the selective area growth model was thus proposed to explain this phenomenon. In addition, the average thin film deposition growth rate was found to be four times higher along (0 0 0 1) than that along {1 0 1¯ 1} facets. As the number of multiple quantum wells was increased, the increase in the barrier thickness also intensified.