Effects of strain‐control layers on piezoelectric field and indium incorporation in InGaN/GaN blue quantum wells

We investigated the effects of a strain‐control layer on piezoelectric fields and indium incorporation in blue‐emitting InGaN/GaN quantum wells (QWs) using reverse‐biased electroreflectance spectroscopy. With this technique, we could determine the change in both indium incorporation and the piezoelectric field by the inserted buffer layer. We compared two test samples, which have identical structures except for the insertion of an additional InGaN layer at the bottom of the blue‐QW. The magnitude of the piezoelectric fields in the QWs with the added layer was significantly smaller even with a slightly higher indium composition. The result shows that the strain in the QW is partially released and can be controlled quantitatively by the strain‐control layer underneath. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)