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 analogy between electromagnetic wave propagation in multidimensionally periodic structures and electron-wave propagation in real crystals has proven to be a fruitful one. Initial efforts were motivated by the prospect of a photonic band gap. a frequency band in three-dimensional dielectric structures in which electromagnetic waves are forbidden irrespective of the propagation direction in space. Today many new ideas and applications are being pursued in two and three dimensions and in metallic, dielectric, and acoustic structures. We review the early motivations for this research, which were derived from the need for a photonic band gap in quantum optics. This need led to a series of experimental and theoretical searches for the elusive photonic band-gap structures, those three-dimensionally periodic dielectric structures that are to photon waves as semiconductor crystals are to electron waves. We describe how the photonic semiconductor can be doped, producing tiny electromagnetic cavities. Finally, we summarize some of the anticipated implications of photonic band structure for quantum electronics and for other areas of physics and electrical engineering.

/pdf/photonic-band-gap-structures-368vs9hzo5.pdf

Photonic band-gap structures

This paper reviews the work on cavity quantum electrodynamics of free atoms. In recent years, cavity experiments have also been conducted on a variety of solid-state systems resulting in many interesting applications, of which microlasers, photon bandgap structures and quantum dot structures in cavities are outstanding examples. Although these phenomena and systems are very interesting, discussion is limited here to free atoms and mostly single atoms because these systems exhibit clean quantum phenomena and are not disturbed by a variety of other effects. At the centre of our review is the work on the one-atom maser, but we also give a survey of the entire field, using free atoms in order to show the large variety of problems dealt with. The cavity interaction can be separated into two main regimes: the weak coupling in cavity or cavity-like structures with low quality factors Q and the strong coupling when high-Q cavities are involved. The weak coupling leads to modification of spontaneous transitions and level shifts, whereas the strong coupling enables one to observe a periodic exchange of photons between atoms and the radiation field. In this case, atoms and photons are entangled, this being the basis for a variety of phenomena observed, some of them leading to interesting applications in quantum information processing. The cavity experiments with free atoms reached a new domain with the advent of experiments in the visible spectral region. A review on recent achievements in this area is also given.

https://iopscience.iop.org/article/10.1088/0034-4885/69/5/R02/pdf

Cavity quantum electrodynamics

Within a time span of 15 years, acoustic metamaterials have emerged from academic curiosity to become an active field driven by scientific discoveries and diverse application potentials. This review traces the development of acoustic metamaterials from the initial findings of mass density and bulk modulus frequency dispersions in locally resonant structures to the diverse functionalities afforded by the perspective of negative constitutive parameter values, and their implications for acoustic wave behaviors. We survey the more recent developments, which include compact phase manipulation structures, superabsorption, and actively controllable metamaterials as well as the new directions on acoustic wave transport in moving fluid, elastic, and mechanical metamaterials, graphene-inspired metamaterials, and structures whose characteristics are best delineated by non-Hermitian Hamiltonians. Many of the novel acoustic metamaterial structures have transcended the original definition of metamaterials as arising from the collective manifestations of constituent resonating units, but they continue to extend wave manipulation functionalities beyond those found in nature.

/pdf/acoustic-metamaterials-from-local-resonances-to-broad-4s4297ihw6.pdf

Acoustic metamaterials: From local resonances to broad horizons.

Elastic and acoustic wave band structure

We employ the concepts of band theory to describe the behavior of electromagnetic waves in three dimensionally periodic face-centered-cubic (fcc) dielectric structures. This can produce a ``photonic band gap'' in which optical modes, spontaneous emission, and zero-point fluctuations are all absent. In the course of a broad experimental survey, we have found that most fcc dielectric structures have ``semimetallic'' band structure. Nevertheless, we have identified one particular dielectric ``crystal'' which actually has a ``photonic band gap.'' This dielectric structure, consisting of 86% empty space, requires a refractive index contrast greater than 3 to 1, which happens to be readily obtainable in semiconductor materials.

/pdf/photonic-band-structure-the-face-centered-cubic-case-wv7ayzjd5t.pdf

Photonic band structure: The face-centered-cubic case.

A method for removing an epitaxial film from a single crystal substrate upon which it is grown and adhering the films to second substrate and the resultant structure. The removing method comprises (a) providing a thin release layer (≦100 nm) between the film to be grown and the single crystal substrate; (b) growing the epitaxial film; (c) applying a polymeric support layer which is under tension over the film; and (d) selectively etching the release layer, the tension in the support layer causing the edges of the film to curve upwardly as the release layer is etched away. The adhering method uses either adhesives or relies solely on Van der Waals bonding between the epitaxial film and the second substrate.

Lift-off and subsequent bonding of epitaxial films

A method for removing epitaxial films from a single crystal substrate upon which it is grown comprising (a) providing a thin release layer (≦1000A) between the film to be grown and the substrate; (b) growing the epitaxial film(s); (c) applying a polymeric support layer which is under tension over the film; and (d) selectively etching the release layer, the tension in the support layer causing the edges of the film to curve upwardly as the release layer is etched away.

Method for lifting-off epitaxial films

A method of passivating the surface of a gallium arsenide substrate by cleaning the gallium arsenide substrate in an etching solution and depositing a sulfide film on the substrate. The step of depositing the sulfide film is preferably performed by spin-on of a sodium sulfide solution, followed by drying or annealing. The resulting passivated surface exhibits superior surface recombination velocity characteristics compared to prior art passivation techniques, thereby making possible superior solid state device operating characteristics.

Passivation of gallium arsenide surfaces with sodium sulfide

We employ the concepts of band theory to describe the behavior of electromagnetic waves in three-dimensionally periodic face-centered-cubic (fcc) dielectric structures. This can produce a “photonic band gap” in which optical modes, spontaneous emission, and zero point fluctuations are all absent. In the course of a broad experimental survey, we have found that most fcc dielectric structures have “semimetallic” band structure. Nevertheless, we have identified one particular dielectric “crystal” that actually has a “photonic band gap.” This dielectric structure consisting of 86% empty space, requires a refractive-index contrast of greater than 3:1, which happens to be readily obtainable in semiconductor materials.

Thomas J. Gmitter

Papers

Photonic band structure: The face-centered-cubic case.

Lift-off and subsequent bonding of epitaxial films

Method for lifting-off epitaxial films

Passivation of gallium arsenide surfaces with sodium sulfide

Photonic band structure: the face-centered-cubic case