Comparative micro-photoluminescence investigation of ZnO hexagonal nanopillars and the seeding layer grown on 4H-SiC
2012 (English)In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 132, no 1, 122-127 p.Article in journal (Refereed) Published
We report on a comparative micro-photoluminescence investigation of ZnO hexagonal nanopillars (HNPs) and the seeding layer grown on the off-axis 4H-SiC substrate. Transmission electron microscope (TEM) results establish that a thin seeding layer continuously covers the terraces of 4H-SiC prior to the growth of ZnO HNPs. Low temperature photoluminescence (LTPL) shows that ZnO HNPs are only dominated by strong donor bound exciton emissions without any deep level emissions. Micro-LTPL mapping demonstrates that this is specific also for the seeding layer. To further understand the recombination mechanisms, time-resolved micro-PL spectra (micro-TRPL) have been collected at 5 K and identical bi-exponential decays have been found on both the HNPs and seeding layer. Temperature-dependent TRPL indicates that the decay time of donor bound exciton is mainly determined by the contributions of non-radiative recombinations. This could be explained by the TEM observation of the non-radiative defects in both the seeding layer and HNPs, like domain boundaries and dislocations, generated at the ZnO/SiC interface due to biaxial strain.
Place, publisher, year, edition, pages
Elsevier, 2012. Vol. 132, no 1, 122-127 p.
ZnO nanopillars, Micro-photoluminescence, Time-resolved PL
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-73577DOI: 10.1016/j.jlumin.2011.08.015ISI: 000302662600024OAI: oai:DiVA.org:liu-73577DiVA: diva2:474700
funding agencies|EU| MRTN-CT-2006-035735 |Swedish Research Council||2012-01-092012-01-092013-09-20Bibliographically approved