The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

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A comprehensive review of zno materials and devices

An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

The optical properties of wurtzite-structured InN grown on sapphire substrates by molecular-beam epitaxy have been characterized by optical absorption, photoluminescence, and photomodulated reflectance techniques. These three characterization techniques show an energy gap for InN between 0.7 and 0.8 eV, much lower than the commonly accepted value of 1.9 eV. The photoluminescence peak energy is found to be sensitive to the free-electron concentration of the sample. The peak energy exhibits very weak hydrostatic pressure dependence, and a small, anomalous blueshift with increasing temperature.

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Unusual properties of the fundamental band gap of InN

Wide-band-gap GaN and Ga-rich InGaN alloys, with energy gaps covering the blue and near-ultraviolet parts of the electromagnetic spectrum, are one group of the dominant materials for solid state lighting and lasing technologies and consequently, have been studied very well. Much less effort has been devoted to InN and In-rich InGaN alloys. A major breakthrough in 2002, stemming from much improved quality of InN films grown using molecular beam epitaxy, resulted in the bandgap of InN being revised from 1.9 eV to a much narrower value of 0.64 eV. This finding triggered a worldwide research thrust into the area of narrow-band-gap group-III nitrides. The low value of the InN bandgap provides a basis for a consistent description of the electronic structure of InGaN and InAlN alloys with all compositions. It extends the fundamental bandgap of the group III-nitride alloy system over a wider spectral region, ranging from the near infrared at ∼1.9 μm (0.64 eV for InN) to the ultraviolet at ∼0.36 μm (3.4 eV for GaN...

When group-III nitrides go infrared: New properties and perspectives

During the last few years the interest in the indium nitride (InN) semiconductor has been remarkable. There have been significant improvements in the growth of InN films. High quality single crystalline InN film with two-dimensional growth and high growth rate are now routinely obtained. The background carrier concentration and Hall mobility have also improved. Observation of strong photoluminescence near the band edge is reported very recently, leading to conflicts concerning the exact band gap of InN. Attempts have also been made on the deposition of InN based heterostructures for the fabrication of InN based electronic devices. Preliminary evidence of two-dimensional electron gas accumulation in the InN and studies on InN-based field-effect transistor structure are reported. In this article, the work accomplished in the InN research, from its evolution to till now, is reviewed. The In containing alloys or other nitrides (AlGaInN, GaN,AlN) are not discussed here. We mainly concentrate on the growth, characterization, and recent developments in InN research. The most popular growth techniques, metalorganic vapor phase epitaxy and molecular beam epitaxy, are discussed in detail with their recent progress. Important phenomena in the epitaxialgrowth of InN as well as the problems remaining for future study are also discussed.

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Indium nitride (InN): A review on growth, characterization, and properties

Room-temperature observation of ferromagnetism in diluted magnetic semiconductor GaGdN grown by RF-molecular beam epitaxy

We have investigated the growth temperature dependence of InN crystalline quality grown by RF-MBE. It was confirmed that the crystalline quality improved by increasing the growth temperature within the dissociation limit of InN. We obtained FWHM as narrow as 3.7 cm -1 for E 2 (high frequency) phonon mode peak of Raman spectroscopy and 24 meV for the band-edge luminescence at 77 K. These values prove excellent quality of our samples. In this study, we obtained optical band-gap energy of around 0.8 eV at room temperature from the high-quality InN samples.

Growth Temperature Dependence of Indium Nitride Crystalline Quality Grown by RF‐MBE

We succeeded in growing InN films two-dimensionally by radio-frequency plasma-excited molecular beam epitaxy (RF-MBE), using a low-temperature-grown InN buffer layer. From the results of reflection high-energy electron diffraction (RHEED) observation and X-ray diffraction (XRD) measurement, it was found that a single crystal of InN films with a wurtzite structure was obtained. Moreover, from the results of Hall effect measurement, it was found that the InN films had quite high electron mobilities. The best electron mobility at room temperature obtained in this study was 760 cm2/Vs and the corresponding carrier density was 3.0×1019 cm-3. To our knowledge, this electron mobility is the highest value ever reported for single crystal InN films.

https://iopscience.iop.org/article/10.1143/JJAP.40.L91/pdf

Growth of High-Electron-Mobility InN by RF Molecular Beam Epitaxy

A silicon carbide field-effect transistor is provided which includes a semiconductor substrate, a channel formation layer of silicon carbide formed above the substrate, source and drain regions provided in contact with the channel formation layer, a gate insulator disposed between the source and drain regions, and a gate electrode formed on the gate insulator, wherein a first contact between the channel formation layer and the drain region exhibits different electric characteristics from those of a second contact between the channel formation layer and the source region. Also provided is a method for producing such a silicon carbide field-effect transistor.

Silicon carbide field-effect transistor with improved breakdown voltage and low leakage current

A process for producing a SiC semiconductor device comprising growing a single-crystal film of SiC on a single-crystal substrate of Si and forming the structure of semiconductor device such as diodes, transistors, etc., on said SiC single-crystal film, thereby obtaining a SiC semiconductor device on a commercial scale.

Akira Suzuki

Papers

Room-temperature observation of ferromagnetism in diluted magnetic semiconductor GaGdN grown by RF-molecular beam epitaxy

Growth Temperature Dependence of Indium Nitride Crystalline Quality Grown by RF‐MBE

Growth of High-Electron-Mobility InN by RF Molecular Beam Epitaxy

Silicon carbide field-effect transistor with improved breakdown voltage and low leakage current

Process for producing a SiC semiconductor device