Challenges and opportunities of ZnO-related single crystalline heterostructures

Journal Article · Sat Mar 15 00:00:00 EDT 2014 · Applied Physics Reviews

DOI:https://doi.org/10.1063/1.4853535· OSTI ID:22269577

Kozuka, Y. ^[1]; Tsukazaki, A. ^[2]

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1. Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan)
2. Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

Recent technological advancement in ZnO heterostructures has expanded the possibility of device functionalities to various kinds of applications. In order to extract novel device functionalities in the heterostructures, one needs to fabricate high quality films and interfaces with minimal impurities, defects, and disorder. With employing molecular-beam epitaxy and single crystal ZnO substrates, the density of residual impurities and defects can be drastically reduced and the optical and electrical properties have been dramatically improved for the ZnO films and heterostructures with Mg{sub x}Zn{sub 1-x}O. Here, we overview such recent technological advancement from various aspects of application. Towards optoelectronic devices such as a light emitter and a photodetector in an ultraviolet region, the development of p-type ZnO and the fabrication of excellent Schottky contact, respectively, have been subjected to intensive studies for years. For the former, the fine tuning of the growth conditions to make Mg{sub x}Zn{sub 1-x}O as intrinsic as possible has opened the possibilities of making p-type Mg{sub x}Zn{sub 1-x}O through NH{sub 3} doping method. For the latter, conducting and transparent polymer films spin-coated on Mg{sub x}Zn{sub 1-x}O was shown to give almost ideal Schottky junctions. The wavelength-selective detection can be realized with varying the Mg content. From the viewpoint of electronic devices, two-dimensional electrons confined at the Mg{sub x}Zn{sub 1-x}O/ZnO interfaces are promising candidate for quantum devices because of high electron mobility and strong electron-electron correlation effect. These wonderful features and tremendous opportunities in ZnO-based heterostructures make this system unique and promising in oxide electronics and will lead to new quantum functionalities in optoelectronic devices and electronic applications with lower energy consumption and high performance.

• OSTI ID: 22269577
• Journal Information: Applied Physics Reviews, Vol. 1, Issue 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1931-9401
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
36 MATERIALS SCIENCE
AMMONIA
DEFECTS
DENSITY
DETECTION
ELECTRICAL PROPERTIES
ELECTRON CORRELATION
ELECTRON MOBILITY
ELECTRONIC EQUIPMENT
ELECTRONS
FABRICATION
FILMS
IMPURITIES
MOLECULAR BEAM EPITAXY
MONOCRYSTALS
POLYMERS
SUBSTRATES
WAVELENGTHS
ZINC OXIDES