Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

Wei Niu, Yulin Gan, Dennis Valbjørn Christensen, Merlin von Soosten, Xuefeng Wang, Yongbing Xu, Rong Zhang, Nini Pryds, Yunzhong Chen

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The two-dimensional electron gas (2DEG) at the non-isostructural interface between spinel γ-Al2O3 and perovskite SrTiO3 is featured by a record electron mobility among complex oxide interfaces in addition to a high carrier density up to the order of 1015 cm-2. Herein, we report on the patterning of 2DEG at the γ-Al2O3/SrTiO3 interface grown at 650 °C by pulsed laser deposition using a hard mask of LaMnO3. The patterned 2DEG exhibits a critical thickness of 2 unit cells γ-Al2O3 for the occurrence of interface conductivity, similar to the unpatterned sample. However, its maximum carrier density is found to be approximately 3×1013 cm-2, much lower than that of the unpatterned sample (~1015 cm-2). Remarkably, a high electron mobility of approximately 3,600 cm2V-1s-1 was obtained at low temperatures for the patterned 2DEG at a carrier density of ~ 7×1012 cm-2, which exhibits clear Shubnikov-de Hass quantum oscillations. The patterned high-mobility 2DEG at the γ-Al2O3/SrTiO3 interface paves the way for the design and application of spinel/perovskite interfaces for high-mobility all-oxide electronic devic
Original languageEnglish
Article number021602
JournalApplied Physics Letters
Issue number2
Number of pages4
Publication statusPublished - 2017


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