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Abstract: InGaN/GaN single quantum well (SQW) structures under various InGaN growth temperatures have been grown by metal organic chemical vapor deposition (MOCVD), the surface morphologies and optical properties are investigated. The radius of the typical V-pits on the SQW surface is affected by the InGaN well-temperature, and the surface roughness decreased as the well-temperature reduced. Room-temperature photoluminescence (PL) and cathode luminescence (CL) shows the quantum well and quantum dot (QD)-like localized state light emission of the SQWs grown at 700 and 690°C, respectively, whereas the samples grown at 670 and 650°C present hybrid emission peaks. Excitation power dependent PL spectra indicates the QD-like localized state emission dominates at low excitation power and the quantum well emission starts to take over at high excitation power. [Copyright &y& Elsevier]

Abstract: Selective area epitaxy has been applied to grow GaN stripe templates with side facts, followed by InGaN/GaN multiple quantum well (MQW) structures. Stripes oriented along the direction of [11−20] form smooth triangular {1−101} facets, while stripes in the [1−100] direction produce incomplete coalesced {11−22} side facets with planar (0001) surface under the same growth conditions. Room-temperature luminescence property is investigated by using photoluminescence (PL) and cathodeluminescence (CL) spectra. It is found that uniform emission at 400nm has been obtained for triangular MQWs oriented the direction of [11−20]. With respect to the MQWs grown along the [1−100] direction, large redshift is achieved for the ridge area compared to the sidewall due to the lateral vapor diffusion and surface migration. [Copyright &y& Elsevier]

Abstract: The effect of alloying and expitaxial mismatch strain on the surface ultraviolet (UV) emission efficiencies of AlxGa1−xN films, pseudomorphically grown on both c- and m-plane AlyGa1−yN templates (x−0.03+1.79x−0.06x2 (0

Abstract: We have grown Fe3N films on GaN(0002) substrates by metalorganic chemical vapor deposition (MOCVD). Under lower growth temperatures, small iron particles were formed on GaN surface, while under higher growth temperatures, Fe3N films were formed. The surface morphology of samples with different growth temperatures were characterized by atomic force microscopy. In X-ray Photoelectron Spectroscopy (XPS) measurement, the coexistence of metallic Fe and Fe2+ or Fe3+ was observed in the sample grown at 600°C, while the sample grown at 1050°C showed only high valence forms of Fe ions. It was also found that the magnetic moments of Fe3N prefer to align normal to the c-axis. [Copyright &y& Elsevier]

Abstract: This paper reports the high mobility InN film grown by MOCVD with GaN buffer layer on sapphire substrates. Different buffer layers are used in our experiments. These buffer layers included the annealing sapphire substrate, the low-temperature GaN layer (LT-GaN), the high-temperature GaN layer (HT-GaN) and the complex buffer layer with HT-GaN on LT-GaN. The crystalline quality of the InN film is sensitive to the underlying buffer layer when the film is grown under the high effect V/III ratio condition. And the growth conditions are optimized in our system. We employed the three-step buffer layer with HT-GaN and LT-GaN on annealing sapphire. The mirror like layers on 2in sapphire wafers was obtained. The structure, optical and electrical characteristics of InN was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), photoluminescence (PL) and IR optical absorption. The PL and the absorption studies of the materials reveal a marked energy band gaps structure around 0.70eV, at room temperature. The uniformity of morphology and the electrical property of the grown InN film are markedly improved by using the complex buffer layer with HT-GaN and LT-GaN on the annealing sapphire. The InN film grown by this buffer layer has the carrier concentration of 3.9×1018 cm−3 and the Hall mobility of 939cm2/Vs. [Copyright &y& Elsevier]

Mn-doped films were grown in an ammonia-source HVPE system. Mn3GaN0.5 and GaN were detected in film samples without other phase when the HCl–Mn/NH3 ratio range from 1/200 to 1/100. (GaxMn1-x)N phase also formed in films. Two broad bands centered at 305 and 674 cm-1and new peaks at wave numbers of 592 cm-1arised in Raman spectra of Mn-doped films. It was also found that A1(LO) modes of all Mn-doped samples were strongly asymmetric and showed a considerable redshift. Mn-doped films showed an obvious hysteresis loops at room temperature. Mn-doped films showed metallic characteristic and this mixed structure may be greatly beneficial to spin injection magnetotransport devices. [Copyright &y& Elsevier]

Abstract: The LiNbO 3 thin films are successfully grown by pulsed-laser deposition on theAl 0.28 Ga 0.72 N/GaN substrate. The films are characterized by the X-ray diffraction and the X-ray photoelectron spectroscopy. The ferroelectric properties are measured by the piezoresponse force microscopy. An Al/SiO 2 /LiNbO 3 /Al 0.28 Ga 0.72 N/GaN structure is then fabricated and measured by high frequency capacitance–voltage at 1MHz. The mechanism of interaction between interfaces is revealed. [Copyright &y& Elsevier]