Challenges and opportunities of ZnO-related single crystalline heterostructures

Abstract

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 (MBE) 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 MgxZn1-xO. 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 MgxZn1-xO as intrinsic as possible has opened the possibilities of making p-type MgxZn1-xO through NH3 doping method. For the latter, conducting and transparent polymer films spin-coated on MgxZn1-xO 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 MgxZn1-xO/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.

54 pages, 22 figures

References in corpus (10)

• Measurements of the density-dependent many-body electron mass in 2D GaAs/AlGaAs Heterostructures
• Spin-independent origin of the strongly enhanced effective mass in a dilute 2D electron system
• Spin susceptibility and effective mass of two-dimensional electrons in MgxZn1-xO/ZnO heterostructures
• Effective mass suppression in dilute, spin-polarized two-dimensional electron systems
• Insulating phase of a two-dimensional electron gas in MgZnO/ZnO heterostructure below nu = 1/3
• Temperature dependent magnetotransport around $\nu$= 1/2 in ZnO heterostructures
• Valley splitting of Si/SiGe heterostructures in tilted magnetic fields
• Spin Susceptibility of Interacting Two-dimensional Electrons with Anisotropic Effective Mass
• Control of Electron Spin Coherence Using Landau Level Quantization in a Two-Dimensional Electron Gas
• Precise calibration of Mg concentration in MgxZn1-xO thin films grown on ZnO substrates

Cited by in corpus (17)

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• Optical manifestation of the Stoner ferromagnetic transition in 2D electron systems
• Quantum phase transition in ultrahigh mobility SiGe/Si/SiGe two-dimensional electron system
• Recent developments in the field of the metal-insulator transition in two dimensions
• Topological Properties and Functionalities in Oxide Thin Films and Interfaces
• Quantum oscillations in diamond field effect transistors with a h-BN gate dielectric
• Spin-flip excitations and Stoner ferromagnetism in a strongly correlated quantum Hall system
• Andreev reflection at the interface with an oxide in the quantum Hall regime
• Interaction-Driven Distinctive Electronic States of Artificial Atoms at the ZnO Interface
• Ferroelectricity driven-resistive switching and Schottky barrier modulation at CoPt/MgZnO interface for non-volatile memories
• Large nonvolatile control of magnetic anisotropy in CoPt by a ferroelectric ZnO-based tunneling barrier
• Tilt-Induced Phase Transitions in Even-Denominator Fractional Quantum Hall States at the ZnO Interface
• Quantised conductance of one-dimensional strongly-correlated electrons in an oxide heterostructure
• Spin effect on the low-temperature resistivity maximum in a strongly interacting 2D electron system
• Disappearence of the Aharonov-Bohm Effect for Interacting Electrons in a ZnO Quantum Ring
• Nonlinear response of a MgZnO/ZnO heterostructure close to zero bias