Hiroshi Amano 교수

Atmospheric pressure metalorganic vapor phase epitaxial growth and characterization of high quality GaN on sapphire (0001) substrates are reported. Using AlN buffer layers, GaN thin films with optically flat surfaces free from cracks are successfully grown. The narrowest x-ray rocking curve from the (0006) plane is 2.70′ and from the (202̄4) plane is 1.86′. Photoluminescence spectra show strong near band edge emission. The growth condition dependence of crystalline quality is also studied.

Distinct p-type conduction is realized with Mg-doped GaN by the low-energy electron-beam irradiation (LEEBI) treatment, and the properties of the GaN p-n junction LED are reported for the first time. It was found that the LEEBI treatment drastically lowers the resistivity and remarkably enhances the PL efficiency of MOVPE-grown Mg-doped GaN. The Hall effect measurement of this Mg-doped GaN treated with LEEBI at room temperature showed that the hole concentration is ∼2·10 16 cm -3 , the hole mobi

Gallium nitride (GaN) is a compound semiconductor that has tremendous potential to facilitate economic growth in a semiconductor industry that is silicon-based and currently faced with diminishing returns of performance versus cost of investment. At a material level, its high electric field strength and electron mobility have already shown tremendous potential for high frequency communications and photonic applications. Advances in growth on commercially viable large area substrates are now at t

Solid state UV emitters have many advantages over conventional UV sources. The (Al,In,Ga)N material system is best suited to produce LEDs and laser diodes from 400 nm down to 210 nm-due to its large and tuneable direct band gap, n-and p-doping capability up to the largest bandgap material AlN and a growth and fabrication technology compatible with the current visible InGaN-based LED production. However AlGaN based UV-emitters still suffer from numerous challenges compared to their visible counte

Growth and luminescence properties of Mg‐doped prepared by metal‐organic vapor phase epitaxy, in which or is used as the Mg source gas, are reported for the first time. It was found that the Mg concentration in is proportional to the flow rate of the Mg source gas; the doping efficiency of Mg into is independent of the substrate temperature from 850° to 1040°C; and Mg in acts as an acceptor and forms blue luminescence centers. By using, an efficient near‐UV and blue LED can be fabricated.

We report the first observation of the room temperature stimulated emission near UV from a GaN film which was grown by metalorganic vapor phase epitaxy on a (0001) sapphire substrate using an AlN buffer layer. This indicates that the GaN film is promising for the realization of an UV laser diode.

In organometallic vapor phase epitaxial growth of GaN on sapphire, the role of the low-temperature-deposited interlayers inserted between high-temperature-grown GaN layers was investigated by in situ stress measurement, X-ray diffraction, and transmission electron microscopy. Insertion of a series of low temperature GaN interlayers reduces the density of threading dislocations while simultaneously increasing the tensile stress during growth, ultimately resulting in cracking of the GaN film. Low

GaN films grown on (11 2̄0) and (0001) sapphire substrates are characterized by X-ray Bond's method and the low temperature photoluminescence measurement. The GaN films are found to be strained by the biaxial compressive stress. From the measured strain and the shift of PL peak energy, the deformation potential of GaN (the relation between the strain parallel to the c -axis and the band gap energy) is found to be 12 eV. The origin of this compressive stress is discussed.