Improvements in Optical Properties of (0001) ZnO Layers Grown on (0001) Sapphire Substrates by Halide Vapor Phase Epitaxy Using Thick Buffer Layers
2012 (English)In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 51, no 3, 031103- p.Article in journal (Refereed) Published
The optical properties of (0001) ZnO layers grown at 1000 degrees C on (0001) sapphire substrates by halide vapor phase epitaxy (HVPE) were investigated by various photoluminescence (PL) measurements. A layer grown with a H2O/ZnCl2 (VI/II) ratio of 20 on a 0.4-mu m-thick buffer layer exhibited a significant near-band-edge (NBE) peak blueshift and degraded internal quantum efficiency (eta(int)) due to residual compressive stress. Growth with a VI/II ratio of 600 diminished the NBE peak blueshift; however, deep level emission and a reduction of PL decay time (tau(PL)) were caused by point defects generated by excess O source supply. A layer without the NBE peak blueshift and deep level emission was realized by growth with a VI/II ratio of 20 and a buffer layer of 0.8 mu m. The eta(int) and tau(PL) for HVPE-grown layers could be improved to 4.1% and 122.8 ps by using the thick buffer layer and appropriate VI/II ratio.
Place, publisher, year, edition, pages
Japan Society of Applied Physics , 2012. Vol. 51, no 3, 031103- p.
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-76529DOI: 10.1143/JJAP.51.031103ISI: 000301348400011OAI: oai:DiVA.org:liu-76529DiVA: diva2:515139
Funding Agencies|Tokyo University of Agriculture and Technology||Japan Society for the Promotion of Science||2012-04-122012-04-112013-05-02