Thermal stability of 2DEG at amorphous LaAlO3/crystalline SrTiO3 heterointerfaces

• Published in: Nano convergence 2016, 3(7), , pp.1-6
• Main Authors: Moon, Seon Young, Moon, Cheon Woo, Chang, Hye Jung, Kim, Taemin, Kang, Chong-Yun, Choi, Heon-Jin, Kim, Jin-Sang, Baek, Seung-Hyub, Jang, Ho Won
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Materials Science; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; 고분자공학
• ISSN: 2196-5404; 2196-5404
• DOI: 10.1186/s40580-016-0067-9

At present, the generation of heterostructures with two dimensional electron gas (2DEG) in amorphous LaAlO 3 (a-LAO)/SrTiO 3 (STO) has been achieved. Herein, we analysed thermal stability of 2DEG at a-LAO/STO interfaces in comparison with 2DEG at crystalline LaAlO 3 (c-LAO)/STO interfaces. To create 2DEG at LAO/STO interface, regardless of growing temperature from 25 to 700 °C, we found that environment with oxygen deficient during the deposition of LAO overlayer is essentially required. That indicates that the oxygen-poor condition in the system is more essential than the crystalline nature of LAO layer. 2DEG at a-LAO/STO interface is depleted upon ex situ annealing at 300 °C under 300 Torr of oxygen pressure, while that in c-LAO/STO interface is still maintained. Our result suggests that the LAO overlayer crystallinity critically affects the thermal-annealing-induced depletion of 2DEG at a-LAO/STO interface rather than the generation of 2DEG. We clearly provide that amorphous TiO x can efficiently prevent the thermal degradation of 2DEG at the a-LAO/STO interface, which gives a cornerstone for achieving thermal-stable 2DEG at a-LAO/STO interface.