We have investigated how the recently-developed water-leaching method for atomically-flat SrTiO3 (STO) substrates affects the transport properties of LaAlO3 (LAO) and STO heterointerfaces. Using pulsed laser deposition at identical growth conditions, we have synthesized epitaxial LAO thin-films on two different STO substrates, which are prepared by water-leaching and buffered hydrofluoric acid (BHF) etching methods. The structural, transport, and optical properties of LAO/STO heterostructures grown on water-leached substrates show the same high-quality as the samples grown on BHF-etched substrates. These results indicate that the water-leaching method can be used to grow complex oxide heterostructures with atomically well-defined heterointerfaces without safety concerns.
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We acknowledge the support of National Science Foundation grant DMR-1454200 for sample synthesis, transport measurements, and optical spectroscopy in addition to a grant from the Kentucky Science and Engineering Foundation as per Grant Agreement #KSEF-148-502-14-328 with the Kentucky Science and Technology Corporation. D.W.K. was supported by the National Research Foundation of Korea Grant (No. 2015001948).
Connell, John G.; Nichols, J.; Gruenewald, John H.; Kim, D. -W.; and Seo, Sung S. Ambrose, "Conducting LaAlO3/SrTiO3 Heterointerfaces on Atomically-Flat Substrates Prepared by Deionized-Water" (2016). Physics and Astronomy Faculty Publications. 398.