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 2024-01-20T04:34:39Z 2024-01-20T04:34:39Z 2021-09-05 2016-03 1738-8090 https://pubs.kist.re.kr/handle/201004/124330 Here we report comprehensive study of 2DEG at a-LAO/STO interfaces in comparison with 2DEG at crystalline LaAlO3 (c-LAO)/STO interfaces. We observe that the oxygen deficient environment during the deposition of LAO overlayer is essentially required to create 2DEG at LAO/STO interface regardless of growth temperature from 25 degrees C to 700 degrees C, indicating that the oxygen-poor condition in the system is more important than the crystallinity of LAO layer. The critical thickness (2.6 nm) of 2DEG formation at a-LAO/STO heterostructure is thicker than (1.6 nm) that at c-LAO/STO. Upon ex-situ annealing at 300 degrees C under 300 mTorr of oxygen pressure, 2DEG at a-LAO/STO interface is annihilated, while that in c-LAO/STO interface is still maintained. With combing these findings and scanning transmission electron microscope (STEM) analysis, we suggest that oxygen vacancies at the LAO surface is attributed to the origin of 2DEG formation at the LAO/STO and the crystallinity of the LAO overlayer plays a critical role in the annihilation of 2DEG at a-LAO/STO interface rather than in the formation of 2DEG. This work provides a framework to understand the importance of prohibiting the LAO surface from being oxidized for achieving thermally stable 2DEG at a-LAO/STO interface. English KOREAN INST METALS MATERIALS 2-DIMENSIONAL ELECTRON-GAS OXIDE INTERFACE MOBILITY CONDUCTIVITY FILMS SUPERCONDUCTIVITY COEXISTENCE PHYSICS CHARGE Comprehensive Study on Critical Role of Surface Oxygen Vacancies for 2DEG Formation and Annihilation in LaAlO3/SrTiO3 Heterointerfaces Article 10.1007/s13391-015-5402-5 1 ELECTRONIC MATERIALS LETTERS, v.12, no.2, pp.243 - 250 ELECTRONIC MATERIALS LETTERS 12 2 243 250 scie scopus kci ART002089461 000371469600008 2-s2.0-84960091991 Materials Science, Multidisciplinary Materials Science Article 2-DIMENSIONAL ELECTRON-GAS OXIDE INTERFACE MOBILITY CONDUCTIVITY FILMS SUPERCONDUCTIVITY COEXISTENCE PHYSICS CHARGE LaAlO3/SrTiO3 2-dimensional electron gas amorphous oxygen vacancy thermal stability