Ga(1-x)In(x)N(y)As(1-y) is a promising material system for the fabrication of inexpensive "last-mile" optoelectronic components. However, details of its atomic arrangement and the relationship to observed optical properties is not fully known. Particularly, a blueshift of emission wavelength is observed after annealing. In this work, we use x-ray absorption fine structure to study the chemical environment around N atoms in the material before and after annealing. We find that as-grown molecular beam epitaxy material consists of a nearly random distribution of atoms, while postannealed material shows segregation of In toward N. Ab initio simulations show that this short-range ordering creates a more thermodynamically stable alloy and is responsible for blueshifting the emission.

α-Ga2O3 is a metastable phase of gallium oxide (Ga2O3) and is important for application in solar-blind region optoelectronic devices. High-quality α-Ga2O3 thin films can be grown by mist chemical vapor deposition (mist-CVD). We systematically investigate the growth mechanism of α-Ga2O3 by mist-CVD using acetylacetonated Ga source solutions. We propose a growth mechanism of α-Ga2O3 in mist-CVD in which acetylacetonate ligands anchor to surface hydroxyls and Ga–O bonds are formed by a ligand exchange mechanism. The origin of oxygen atoms and impurity concentration profiles in grown α-Ga2O3 thin films are examined by secondary ion mass spectroscopy.

Routes to semi-stable phases of Ga[Formula: see text]O[Formula: see text] are the subject of extended discussions based on the review of growth methods, growth conditions, and precursors in works that report semi-stable phases other than the thermally stable [Formula: see text] phase. The focus here is on mist chemical vapor deposition because it has produced single-phase Ga[Formula: see text]O[Formula: see text] of [Formula: see text], [Formula: see text], and [Formula: see text] (or [Formula: see text]) in terms of the substrate materials, and features of this growth method for phase control are emphasized. Recent reports of phase control by other growth technology give a deeper understanding of how to determine and control the phases, increasing the opportunities to fully utilize the novel and unique properties of Ga[Formula: see text]O[Formula: see text].

The growth mechanisms of zinc oxide and zinc sulfide films by mist chemical vapor deposition (mist-CVD) were experimentally investigated from the viewpoint of mist behaviors and chemical reactions. The proper growth model, either vaporization or the Leidenfrost model, was studied by supplying two kinds of mists with different kinds of sources, such as H2 16O and H2 18O for ZnO growth and ZnCl2 and thiourea for ZnS growth. Moreover, the origin of the oxygen atoms of ZnO was investigated using a quantitative analysis. The role of chloro complex of zinc in the growth of ZnS from aqueous solutions was also examined by systematic studies.

We have developed a longitudinally excited CO 2 laser with a short laser pulse similar to that of TEA and Q-switched CO 2 lasers. A capacitor transfer circuit with a low shunt resistance provided rapid discharge and a sharp spike pulse with a short pulse tail. Specifically, a circuit with a resistance of 10 M Ω provided a spike pulse width of 103.3 ns and a pulse tail length of 61.9 μs, whereas a circuit with a shunt resistance of 100 Ω provided a laser pulse with a spike pulse width of 96.3 ns and a pulse tail length of 17.2 μs. The laser pulses from this longitudinally excited CO 2 laser were used for processing a human tooth without carbonization and for glass marking without cracks.