Davis, Jeffrey A.Van Dao, LapWen, XiaomingHannaford, PeterColeman, Victoria AJagadish, C.Koike, K.Sasa, S.Inoue, M.Yano, M.Tan, Hark Hoe2015-11-022015-11-020003-6951http://hdl.handle.net/1885/16212We have studied ZnO∕ZnMgO multiple quantum wells by spectrally resolved transient four-wave mixing with both one- and two-color excitations. The presence of an extended signal at negative interpulse delays in the two-color experiment is attributed to the two-photon coherence resulting from the generation of biexcitons. This technique provides a means to observe a transient four-wave mixing from biexcitons in the absence of any other signal, and thereby provides the first clear evidence that biexcitons are present in narrow ZnO∕ZnMgOquantum wells at room temperature. Dephasing times of the order of 100fs for the biexcitons are measured.The authors gratefully acknowledge The Australian Research Council for financial support and Swinburne University of Technology for Strategic Initiative funding.http://www.sherpa.ac.uk/romeo/issn/0003-6951..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 3/11/15). Copyright 2006 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.2372747Keywords: Coherent light; Excitons; Four wave mixing; Photons; Semiconductor quantum wells; Thermal effects; Transients; Biexcitons; Interpulse delays; Room temperature; Zinc oxide2006-11-0110.1063/1.23727472015-12-08