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Abstract: A series of hot (600 °C) and room temperature C+/Al+ co-implanted 6H–SiC epitaxial films, under different implantation dose levels and high temperature (1550 °C) post-annealing, were studied by a variety of structural and optical characterization techniques, including secondary ion mass spectroscopy, high resolution X-ray diffraction, Fourier transform infrared reflectance, micro-Raman and photoluminescence (PL) spectroscopy. The damage and amorphization of SiC layer by co-implantation, and the elimination/suppression of the implantation induced amorphous layer via high temperature annealing are observed. The recovery of the crystallinity and the activation of the implant acceptors are confirmed. The results from hot or RT co-implantation are compared. [Copyright &y& Elsevier]

Abstract: Two sets of (Al x Ga1−x )0.5In0.5P films were grown on lattice-matched GaAs by low pressure metalorganic chemical vapor deposition under different conditions and studied by Nomarski microscopy (NM), atomic force microscopy (AFM), photoluminescence (PL) and Raman scattering. NM and AFM images show cross-hatch patterns, related to dislocations and lattice mismatch, from one set of samples, but none from another set of films. Comparative PL and Raman measurements and analyses indicated the correlation between surface and optical properties. The degree of variations in compositions and film quality with the growth conditions was found from the spectral analyses. Raman spectral features are more sensitive to the sample growth parameter variations. The line shape analysis of line width, integrated intensity ratio and spatial correlation model fitting leads to information about the order of the sample crystalline quality. The optimum growth conditions have been obtained from our comprehensive analyses. [Copyright &y& Elsevier]

Abstract: The wavelength shifts in the photoluminescence (PL) from low indium composition (∼ 3%) InGaN epitaxial thin films, grown on sapphire substrates by metalorganic chemical vapour deposition, has been studied by a combination of experiment and theory. As temperature increases from 6 K, the PL peak energy red-shifts very slightly first, then blue-shifts to reach a maximum at near 100 K, and red-shifts again till room temperature. This unique PL behaviour, indicating the existence of the phase separation, is interpreted qualitatively from the spatial variation of band structure due to the In-compositional fluctuation. Theoretical calculation, based upon a model involving the band-tail states in the radiative recombination, explains the experimental data successfully. [Copyright &y& Elsevier]

Zn-doped InGaN thin films were deposited on GaN/sapphire by metalorganic chemical vapor deposition, and studied by a combination of high-resolution X-ray diffraction (HR-XRD), micro-photoluminescence (PL) and secondary ion mass spectrometry (SIMS). Indium phase separation is studied comparatively. HR-XRD exhibits a GaN band and a single band from InGaN for samples without phase separation, but two InGaN bands corresponding to different x(In) for samples with phase separation. PL excitation power dependence measurements reveal 2 sets of InGaN PL emissions for samples with phase separation, but only 1 set for samples without phase separation. SIMS data showed that phase separated InGaN:Zn films possess a high Zn concentration near the InGaN–GaN interface and non-uniform distributions of In and Zn contents, which are in contrast with data from InGaN:Zn films with no In-phase separation. [Copyright &y& Elsevier]

Describes the room-temperature photoluminescence, contactless electroreflectance and x-ray characterization of a double-side delta-doped GaAlAs/InGaAs high electron mobility transistor structure. Observation of signals from every region of the sample; Optical determination of the In composition and channel width.

Abstract: Al x In y Ga1−x−y N quaternary alloys with different ratios of Al/In were grown by metal-organic chemical vapor deposition on GaN/Al2O3 substrates. The structural and emission properties of the as-grown samples were investigated, respectively, by high-resolution X-ray diffraction and photoluminescence (PL) measurements. The PL emission character is related to the two prominent quenching bands, which have been determined to be located at around 1.1eV and 1.7eV above the valence band, respectively, by the method of optical quenching of photoconductivity. PL emission is most intense when the Al/In ratio is 7.5 for the Al x In y Ga1−x−y N layer. In addition, a stronger quenching phenomenon with Al/In ratio of 5.0 in Al x In y Ga1−x−y N is observed in accordance with a reduction of the intensity of Al x In y Ga1−x−y N-related emission peak. [Copyright &y& Elsevier]

Abstract: Band gap blue shift of InGaAs/InP multiple quantum well (MQW) structures by impurity-free vacancy disordering (IFVD) is studied by photoluminescence (PL) and secondary ion mass spectrum (SIMS). SiO2, Si3N4, and spin on glass (SOG) were used for the dielectric layers to create the vacancies. The results indicate that the band gap blue shift varies with the different dielectric layers and depends on the annealing temperature. The blue shift is also related to the combination of the layers between dielectric and cladding layers. The SIMS profile shows that the dielectric capped layer and rapid thermal annealing caused the quantum well intermixing, which results in the band gap blue shift. Optimum condition can be reached by choosing suitable dielectric layer and annealing condition. [Copyright &y& Elsevier]

Abstract: A series of GaN thin films were grown on Si substrate under different conditions using metalorganic chemical vapor deposition (MOCVD) and characterized by Nomarski microscopy (NM), optical reflectance (OR), high-resolution X-ray diffraction (HRXRD), Raman scattering (RS) and photoluminescence (PL). NM showed different patterns for GaN/Si grown under different growth and source flow parameters. XRD, RS and PL measurements confirmed their wurtzite crystalline GaN structures, and the corresponding line shape analyses revealed their difference corresponding to the NM observations. The control and improvement of the crystalline cracking in GaN/Si are discussed. [Copyright &y& Elsevier]

Highlights: [•] The properties of the exciton localization energy as well as electron/exciton-phonon interaction are studied by the modified Bose–Einstein equation. [•] The stress is studied by the X-ray diffraction spectra to indicate that the c-axis length decreases as the increasing of Al/In ratio. [•] The decreased compressive stress attributed to the increased tensile stress formed by Al atoms incorporated. [ABSTRACT FROM AUTHOR]

Abstract: Zn0.92Cu0.08O nanorods array were synthesized by radio frequency magnetron sputtering deposition at different substrate temperatures. No extra catalysts were used during synthesis. The structural and photoluminescence properties were investigated. Results showed that the ferromagnetism (FM) observed at 20 °C were an intrinsic property of Cu-doped ZnO nanorods. With the increase in substrate temperature, an improved crystallinity along with the increase in oxygen vacancies was observed in Zn0.92Cu0.08O nanorods, which caused an enhancement of magnetic moment in Zn0.92Cu0.08O nanorods. The experimental results showed that the interaction between substitutional CuZn in a divalent charge and oxygen vacancies played an important role in the origin of ferromagnetism in Zn0.92Cu0.08O nanorods. The observed FM is explained in terms of the defect related mechanism. [Copyright &y& Elsevier]

Abstract: Wurtzite-structure MgxZn1−xO materials with five different compositions of x from 0 to 0.14 were grown on sapphire substrates by metalorganic chemical vapor deposition. It was found that increasing Mg content in the MgxZn1−xO not only increased the band gap energy of the film but was also beneficial to the epitaxial growth of p-type MgxZn1−xO without using any doping sources. In addition, the combined ultraviolet photoluminescence (PL) and Raman scattering spectra were measured with PL–Raman signals obtained together, showing a blue-shift of PL band and variation of resonant Raman multi-order longitudinal optical phonon modes with an increase of Mg content. [ABSTRACT FROM AUTHOR]

Abstract: A new type of large area metal organic chemical vapor deposition (MOCVD) system for the growth of high quality and large size ZnO materials is introduced. Materials properties of the un-doped, n- and p-doped ZnO epi-films grown on sapphire substrates by this MOCVD system are studied by various techniques, including high resolution X-ray diffraction (XRD), UV–Visible optical transmission (OT), photoluminescence (PL) and photoluminescence excitation (PLE), synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS). The wurtzite (w) ZnO crystal structures grown with primary (0002) orientation were identified. Results have shown the high crystalline quality of MOCVD-grown ZnO films, indicated by the narrow XRD, PL and Raman line widths, strong PL signals, sharp OT edge and smooth surface. In particular, high p-type carrier concentration of >1017 cm−3 have been achieved besides the good n-type doping in ZnO. [Copyright &y& Elsevier]

Abstract: We report the successful growth of thin GaN layers on (111) orientated Si substrates utilizing a newly developed pulse source injection molecular beam epitaxial (PSIMBE) technique. RHEED patterns showed that two-dimensional layer-by-layer growth started at a very early stage during deposition (within 20 nm). AFM studies showed that an almost atomically smooth surface was obtained with an area RMS roughness of less than 0.2 nm. The crystal structure and quality were determined from high resolution 2-Theta-Omega scan and exhibited only three strong and sharp lines at 28.56°, 34.70° and 73.05° due to the Si substrate and the single crystalline wurtzite (w-) GaN (0002) and (0004), respectively. Raman scattering study showed the characteristic w-GaN E2 band at 565 wave-numbers and the longitudinal optical (LO) phonon-plasma coupling mode at 731 cm− 1. These data indicate the success of MBE growth of single crystalline w-GaN thin layers on the order of less than 100-nm thick on Si substrates without using a complicated buffer structure. [Copyright &y& Elsevier]