The structural and optical properties of InGaN/GaN multiple quantum wells (MQWs) grown on sapphire by MOCVD have been investigated using high-resolution XRD, PL and TEM. The samples consisted of 10 periods of InGaN wells with 6.5nm thickness. The designed indium compositions were 15, 20, 25 and 30% (samples C15, C20, C25, C30, respectively). The thickness of GaN barrier was 7.5nm. The MQW in sample C15 maintained lattice coherency with the GaN epilayer underneath, the MQWs in the other samples, however, experienced lattice relaxation. The crystallinity of the samples decreased considerably with In concentration. As In composition increased, PL peak energy showed a red-shift, and the FWHM of the peaks increased. The increase in the FWHM is attributed to the defects due to the lattice relaxation. For C25 the PL peak intensity increased sharply in spite of the defects due to the lattice relaxation of the sample. It is concluded that the results are related to the In-rich region due to indium phase separation which was observed by TEM image.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
O Ambacher, J. Phys. D: Appl. Phys. 32, 2653 (1998).
J. W. Matthews and A. E. Blackeslee, J. Crystal Growth 32, 256 (1974).
Y. Narukawa, Y. Kawakami, M. Funato, S. Fujita and S. Nakamura, Appl. Phys. Lett. 70, 981 (1997)
K. Tachibana, T. Someya, Y. Arakawa, R. Werner and Forchel, Appl. Phys. Lett. 75, 2605 (1999)
D. Kapolnek, X. H. Wu, B. Heying, S. Keller, B. P. Keller, U. K. Mishra, S. P. Den Baars and J. S. Speck, Appl. Phys. Lett. 67, 1541 (1995).
Gunther Bauer and Wolfgang Richter, Optical Characterization of Epitaxial Semiconductor Layer (Springer, New York, 1996), pp. 294–298.
Paul F Fewster, X-Ray Scattering from Semiconductors (Imperial College Press, London, 2000), pp. 244–253.
About this article
Cite this article
Kim, CS., Noh, SK., Lee, K. et al. Structural and Optical Properties of InGaN/GaN Multi-Quantum Well Structures with Different Indium Compositions. MRS Online Proceedings Library 764, 335 (2002). https://doi.org/10.1557/PROC-764-C3.35