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InN
Kinds of InN Terms modified by InN Selected AbstractsPersonal imports of drugs to Japan in 2005 , an analysis of import certificatesJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 5 2008K. Tsuji MS Summary Background:, Personal imports of unapproved drugs are made by physicians and patients in Japan. Such imports require submission of a request for an import certificate from the Regional Bureau of Health and Welfare (RBHW). So far, there have been few reports on personal imports of drugs in Japan. Objective:, To assess the extent and nature of personal imports of drugs in Japan. Methods:, The date, product name and amount of drug imported were provided by RBHW for each personal import made by physicians in 2005. All imports were classified into several groups including whether they were for ,prescription drugs for non-cosmetic use (PDNC)' or ,prescription drugs for cosmetic use (PDC)'. Identification of PDNC was made by International Non-proprietary Name (INN). All drugs were classified under therapeutic groups. For the most frequently imported unapproved drugs, the approval year in the US/EU and development status in Japan were recorded. Results:, A total of 12 196 personal imports were initiated by physicians in 2005. 5428 were for PDNCs corresponding to 242 drugs by INN. 55 PDNCs were each the subject of 10 or more imports. 11 drugs (252 imports) out of the top 55 PDNCs were available on the Japanese market during 2005 and 44 (4713 imports) were not approved. Of the 44 unapproved drugs, 11 (1019 imports) had been approved and 10 (2785 imports) were in the pre-registration phase as of December 31, 2006. Of the 44 unapproved drugs, 12 (1213 imports) were approved during 2000,2004, and 17 (3138 imports), during 1995,1999 in the US or EU. While the majority of imported drugs were antineoplastic drugs, drugs for various kinds of non-serious diseases were also imported. Conclusions:, A substantial number of unapproved drugs were being imported to Japan. A formal system for monitoring the use of those drugs should be established. [source] Centchroman, a selective estrogen receptor modulator, as a contraceptive and for the management of hormone-related clinical disordersMEDICINAL RESEARCH REVIEWS, Issue 4 2001M.M. SinghArticle first published online: 12 JUN 200 Abstract DL -Centchroman (67/20; INN: Ormeloxifene)1,2 synthesized at the Central Drug Research Institute, Lucknow, is a nonsteroidal once-a-week oral contraceptive. It was introduced in Delhi in July, 1991,3,5 marketed in India in 1992 as Saheli and Choice-7 (Hindustan Latex Ltd., Thiruvananthapuram) and Centron (Torrent Pharmaceuticals India Ltd., Ahmedabad),4,6 and included in the National Family Welfare Programme in 1995.5 According to post-marketing surveillance,5 ,100,000 women were using this pill and ,1100,000 menstrual cycles were covered until 1996. It is a unique need-oriented contraceptive being effective when taken immediately after coitus or routinely as a weekly pill2,5,19 and has the advantage of less frequent administration. Its contraceptive action is quickly reversible. It has long terminal serum halflife of 168,hr in women and exhibits duration of anti-implantation/estrogen antagonistic action of 120,hr, despite a short (24.1,hr) serum halflife, in the rat. In lactating women, it is excreted in milk in quantities considered unlikely to cause any deleterious effect on suckling babies.20,21 In phase II and III multicentric trials as a contraceptive, children born of method-and-user failure pregnancies showed normal milestones, without any congenital anomaly. Reports of its promising action in the management of certain hormone-related clinical disorders are available. It has an excellent therapeutic index and is considered safe for chronic administration. © 2001 John Wiley & Sons, Inc. Med Res Rev, 21, No. 4, 302,347, 2001 [source] Biosimilars: pharmacovigilance and risk management,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2010Leyre Zuñiga Ph.D. Abstract Biosimilars cannot be authorised based on the same requirements that apply to generic medicines. Despite the fact that the biosimilar and reference drug can show similar efficacy, the biosimilar may exhibit different safety profile in terms of nature, seriousness or incidence of adverse reactions. However, the data from pre-authorisation clinical studies normally are insufficient to identify all potential differences. Therefore, clinical safety of similar biological medicinal products must be monitored closely on an ongoing basis during the post-approval phase including continued risk,benefit assessment. The biosimilar applicant must provide the European Medicines Agency (EMEA) with a risk management plan (EU-RMP) and pharmacovigilance programme with its application, including a description of the potential safety issues associated with the similar biological medicinal product that may be a result of differences in the manufacturing process from the reference biologic. The most critical safety concern relating to biopharmaceuticals (including biosimilars) is immunogenicity. Risk management applies scientifically based methodologies to identify, assess, communicate and minimise risk throughout a drug's life cycle so as to establish and maintain a favourable benefit,risk profile in patients. The risk management plan for biosimilars should focus on heightens the pharmacovigilance measures, identify immunogenicity risk and implement special post-marketing surveillance. Although International Nonproprietary Names (INNs) served as a useful tool in worldwide pharmacovigilance, for biologicals they should not be relied upon as the only means of product identification. Biologicals should always be commercialised with a brand name or the INN plus the manufacturer's name. Copyright © 2010 John Wiley & Sons, Ltd. [source] Tissue distribution of the novel DPP-4 inhibitor BI 1356 is dominated by saturable binding to its target in ratsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 5 2009Holger Fuchs Abstract BI 1356 (INN: linagliptin) is an inhibitor of dipeptidyl peptidase-4 (DPP-4). This study investigated whether saturable binding of BI 1356 to its target DPP-4 occurs in tissues and whether drug accumulation occurs at these sites in vivo. In order to test these hypotheses, the tissue distribution of BI 1356 was determined in wild-type and DPP-4 deficient rats at different dose levels by means of whole body autoradiography and measurement of tissue radioactivity concentrations after single i.v. dosing of [14C]-radio labeled BI 1356. The accumulation behavior of drug-related radioactivity in tissues was further explored in an oral repeat dose study. Tissue levels of [14C]BI 1356 related radioactivity were markedly lower in all investigated tissues of the DPP-4 deficient rats and the difference of the dose-dependent increase of radioactivity tissue levels between both rat strains indicates that tissue distribution at low doses of BI 1356 is dominated by binding of BI 1356 to DPP-4 in tissues. As the binding to DPP-4 is strong but reversible, the tissue binding results in a long terminal half-life in several tissues including plasma. The binding capacity to DPP-4 is, however, limited. In the rat, saturation of DPP-4 binding is suggested at an intravenous dose above 0.01,0.1,mg/kg [14C]BI 1356. As the DPP-4 binding capacity is saturated already at low doses, accumulation of BI 1356 in tissues is unlikely, despite the long persistence of low amounts in the body. Copyright © 2009 John Wiley & Sons, Ltd. [source] Clinical pharmacokinetic studies with INN 00835 (Nemifitide), a novel pentapeptide antidepressantBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 1 2002John P. Feighner Abstract Nemifitide (4-fluoro-L-phenylalanyl-trans-4-hydroxy-L-prolyl-L-arginylglycyl-L-tryptophanamide ditrifluoroacetate) is a novel antidepressant, currently in phase 2/3 clinical trials. The purpose of our phase 1 clinical trials (conducted over a three year period) was to provide safety and pharmacokinetic data to support its clinical development as an antidepressant drug. Single and multiple doses ranging from 18 to 320 mg were administered subcutaneously to healthy volunteers in five phase 1 studies. Plasma concentrations of unchanged parent drug were determined by a validated LC/MS/MS method in blood samples collected at timepoints between 10 min and 72 h after dosing. Nemifitide was rapidly absorbed (Cmax at 10 min) and eliminated (t1/2 15,30 min) in most subjects. Regression and power model analyses were used to evaluate the data. The results indicate that pharmacokinetic parameters: AUC0,t, AUC 0,, and Cmax, were close to dose proportional in the dose range investigated. There was no evidence of systemic accumulation of drug following 5 daily doses. No serious adverse events or clinically significant systemic adverse events occurred at any of the doses investigated in the over 100 subjects dosed in these studies. Drug-related adverse events were limited to local and transient skin reactions (pain and/or erythema) at the injection site, especially at the high doses administered: 240 and 320 mg. Copyright © 2002 John Wiley & Sons, Ltd. [source] Biosimilars: pharmacovigilance and risk management,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2010Leyre Zuñiga Ph.D. Abstract Biosimilars cannot be authorised based on the same requirements that apply to generic medicines. Despite the fact that the biosimilar and reference drug can show similar efficacy, the biosimilar may exhibit different safety profile in terms of nature, seriousness or incidence of adverse reactions. However, the data from pre-authorisation clinical studies normally are insufficient to identify all potential differences. Therefore, clinical safety of similar biological medicinal products must be monitored closely on an ongoing basis during the post-approval phase including continued risk,benefit assessment. The biosimilar applicant must provide the European Medicines Agency (EMEA) with a risk management plan (EU-RMP) and pharmacovigilance programme with its application, including a description of the potential safety issues associated with the similar biological medicinal product that may be a result of differences in the manufacturing process from the reference biologic. The most critical safety concern relating to biopharmaceuticals (including biosimilars) is immunogenicity. Risk management applies scientifically based methodologies to identify, assess, communicate and minimise risk throughout a drug's life cycle so as to establish and maintain a favourable benefit,risk profile in patients. The risk management plan for biosimilars should focus on heightens the pharmacovigilance measures, identify immunogenicity risk and implement special post-marketing surveillance. Although International Nonproprietary Names (INNs) served as a useful tool in worldwide pharmacovigilance, for biologicals they should not be relied upon as the only means of product identification. Biologicals should always be commercialised with a brand name or the INN plus the manufacturer's name. Copyright © 2010 John Wiley & Sons, Ltd. [source] InN@SiO2 Nanomaterials as New Blue Light EmittersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2008Prabhakaran Munusamy Abstract In this article we report blue photoluminescence (, 450 nm) from InN@SiO2 nanomaterials. The InN@SiO2 nanomaterials were prepared by a simple precipitation reaction followed by a solid-state reaction. Various control experiments demonstrate that the interface between the InN and SiO2 seems to play a crucial role in the origin of the blue emission from the InN@SiO2 nanomaterial. The InN@SiO2 nanomaterial was characterized by using analytical methods such as TEM, XRD, Raman, XPS, and photoluminescence spectroscopy, which confirmed the existence of InN on SiO2 with a small excess of nitrogen relative to indium.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] First-Principles Calculations of Anion Vacancies in Oxides and NitridesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2002Isao Tanaka The formation energy, structural relaxation, and defect-induced states of neutral anion vacancies of five oxides (i.e., MgO, Al2O3, ZnO, In2O3, and SnO2) and four nitrides (i.e., AlN, Si3N4, Ge3N4, and InN) are systematically discussed, based on first-principles plane-wave pseudopotential calculations. Two types of polymorphs for each compound are compared. The number of atoms included in the supercells ranged from 54 to 96. When a localized vacancy-induced state appears within the band gap, as in a typical ionic crystal, the formation energy can be well scaled by the band gap of the perfect crystal. On the other hand, when an empty and localized vacancy-induced state is located above the highest occupied band or no localized state is formed, the formation energy has a tendency to be smaller. In compounds such as ZnO and SnO2, the formation energy is dependent largely on the crystal structure. This result can be explained by the transition of the vacancy-induced state from occupied to unoccupied, which is caused by the change in atomic arrangement, as represented by the cation coordination number. [source] Optical properties of InN grown on templates with controlled surface polaritiesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2010Ronny Kirste Abstract The structural and optical properties of InN layers grown on GaN/sapphire templates with controlled Ga-/N-polar surfaces are investigated. Raman spectroscopy and XRD reciprocal space map analysis suggest that the InN layers were grown strain free with a high crystal quality. A line shape analysis of the A1(LO) Raman mode yields to a decreasing carrier concentration for the sample grown on Ga-polar substrate. Low temperature photoluminescence measurements exhibit a shift to lower energies of the luminescence maximum for the sample grown on Ga-polar GaN probably due to a reduced carrier concentration and thus, a decreased Burstein,Moss shift. Following this, we demonstrate that the use of polarity controlled GaN/sapphire substrates leads to unstrained layers with good structural and optical properties. [source] Impact of n-type doping on the terahertz surface emission from c -plane InNPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2010V. M. Polyakov Abstract We theoretically investigate the influence of n-type doping on the terahertz (THz) electric field emission from unbiased c -plane InN surfaces using the ensemble Monte Carlo (MC) method. It is shown that the increase of n-type doping has twofold effect on the THz surface emission. The detrimental effect of electron drift mobility decrease is compensated by doping-derived electrons constructively contributing to the total dynamic dipole responsible for a generation of the THz electric field pulse emission from InN surface. [source] Optical anisotropy of A - and M -plane InN grown on free-standing GaN substratesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2010P. Schley Abstract Wurtzite A - and M -plane InN films were grown by molecular beam epitaxy (MBE) on free-standing GaN substrates. Spectroscopic ellipsometry (SE) in the photon energy range from 0.56 up to 15,eV was applied in order to determine the ordinary and extraordinary complex dielectric function (DF) of InN. A distinct optical anisotropy was found over the whole energy range. The extraordinary absorption edge in comparison to the ordinary one is shifted to higher energies confirming previous studies. The investigations in the upper vacuum-ultraviolet (VUV) spectral range (9.5,15,eV) yielded transition energies for four critical points (CPs) of the band structure (BS) which have not been observed so far. [source] Optical properties of InN grown on Si(111) substratePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2010E. Sakalauskas Abstract A comprehensive characterization of the optical properties of wurtzite InN films grown by molecular beam epitaxy on Si(111) substrates is presented. Two types of films are investigated in this work: InN on AlN/Si(111) and InN on GaN/AlN/Si(111). Their properties are compared to a layer deposited on GaN/sapphire substrate. The dielectric function (DF) is obtained from spectroscopic ellipsometry (SE). The infrared studies yield the plasma frequency and thus the electron density, while the interband absorption is probed between 0.56 and 9.8,eV. For InN grown on Si(111) substrate, the absorption onset is slightly shifted to higher energies with respect to the InN film grown on GaN/sapphire which can be attributed to higher electron concentrations. Despite this, strongly pronounced optical transitions due to critical points of the band structure are found in the high-energy part of the DF. It emphasizes the already promising quality of the InN films on silicon. Band-gap renormalization (BGR), band filling, and strain are taken into account in order to estimate the intrinsic band gap of wurtzite InN. For the InN layers on silicon, we get a band gap between 0.66 and 0.685,eV. [source] MOVPE of InN films on GaN templates grown on sapphire and silicon(111) substratesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2008Muhammad Jamil Abstract This paper reports the study of MOVPE of InN on GaN templates grown on sapphire and silicon(111) substrates. Thermodynamic analysis of MOVPE of InN performed using NH3 as nitrogen source and the experimental findings support the droplet-free epitaxial growth of InN under high V/III ratios of input precursors. At a growth pressure of 500 Torr, the optimum growth temperature and V/III ratio of the InN film are 575,650 °C and >3 × 105, respectively. The surface RMS roughness of InN film grown GaN/sapphire template is ,0.3 nm on 2 ,m × 2 ,m area, while the RMS roughness of the InN film grown on GaN/Si (111) templates is found as ,0.7 nm. The X-ray diffraction (XRD) measurement reveals the (0002) texture of the InN film on GaN/sapphire template with a FWHM of 281 arcsec of the InN (0002) , rocking curve. For the film grown on GaN/Si template under identical growth conditions, the XRD measurements show the presence of metallic In, in addition to the (0002) orientation of InN layer. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Doping-dependence of subband energies in quantized electron accumulation at InN surfacesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2007T. D. Veal Abstract Electron tunnelling spectroscopy is used to investigate the quantized electron accumulation at the surfaces of wurtzite InN with different doping levels. The tunnelling spectra of InN-oxide-tip junctions recorded in air at room temperature exhibit a ,0.6 V plateau, corresponding to the band gap of InN, and a gap between onsets of 1.3 V, consistent with the separation between the valence band maximum and the pinned Fermi level at the oxidized InN surface. Also observed within the tunnelling spectra are additional features between the conduction band minimum and the pinned Fermi level. These features are attributed to surface-bound quantized states associated with the potential well formed by the downward band bending at the InN-oxide interface. Their energetic positions are dependent upon the doping level of the InN films and coincide with calculated subband energies. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High-quality InN grown on KOH wet etched N-polar InN template by RF-MBEPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2006D. Muto Abstract We have succeeded in dramatically decreasing the density of dislocations in InN by regrowing InN films on micro-facetted N-polar InN templates. The micro-facetted N-polar InN templates were formed by wet etching in a 10 mol/l KOH solution. InN films were regrown on the micro-facetted N-polar InN templates and on flat surface N-polar InN templates for comparison by radio-frequency plasma-assisted molecular beam epitaxy. InN regrown on micro-facetted InN had considerably smaller twist distribution than that grown on the flat InN templates. From transmission electron microscopy observation, it was confirmed that the InN grown on the micro-facetted InN template had much lower density of dislocations than that grown on the flat InN template, and moreover the propagation of edge dislocations was almost completely terminated at the interface between the regrown InN and the micro-facetted InN template. Based on the results, we propose that regrowth of InN on micro-facetted InN templates is an effective way to obtain high-quality InN films. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Stoichiometry effects and the Moss,Burstein effect for InNPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2006K. S. A. Butcher Abstract We examine the Moss,Burstein effect for InN and demonstrate an independent method for determing its magnitude for high carrier concentration material. Consequently it is shown that the extent of the Moss,Burstein effect is less than 0.72 eV for a high carrier concentration sample with a 1.88 eV absorption edge. Early results are also provided for high band-gap low carrier concentration InN films that can be grown reprodcibly, vindicating the work of early groups in the field. The role of stoichiometry is examined in relation to point defects that appear to be common to many forms of InN. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Recombination processes with and without momentum conservation in degenerate InNPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2006E. Valcheva Abstract We report on a theoretical approach in which the two cases of recombination with and without momentum conservation in optically excited high carrier concentration InN are considered. The calculations are used to analyze emission spectra of n-type InN layers of electron concentrations from 7.7 × 1017 to 1.4 × 1019 cm,3 studied in the temperature range between 9 and 100 K. The spectra peak near 0.7 eV and the applicability of the two approaches with increasing carrier concentration is estimated. Different transition mechanisms are considered in order to properly account for the observed features in the spectra. Recombination processes involving acceptor- and donor-like localized states are discussed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Investigation of InN layers grown by MOCVD using analytical and high resolution TEM: The structure, band gap, role of the buffer layersPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2006P. Ruterana Abstract In this work we investigate the microstructure of InN layers grown by MOCVD on different buffer layers using TEM (InN, GaN). The large mismatch between the various lattices (InN, sapphire or GaN) leads to particular interface structures. Our local analysis allows to show that at atomic scale, the material has the InN lattice parameters and that no metallic In precipitates are present, meaning that the PL emission below 0.8 eV is a genuine property of the InN semiconductor. It is also shown that the N polar layers, which exhibit a 2D growth, have poorer PL emission than In polar layers. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Elastic properties of nanowiresPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2010Claus-Christian Röhlig Abstract The elastic properties of metallic and semiconducting nanowires were analyzed by different techniques employing static and dynamic loads. The reliability of the methods is verified by analyzing well defined microstructures and a good agreement for the values of the Young's modulus determined by the different methods was achieved. For the investigated materials systems (Au, W, Si, InN), basically no differences in the Young's moduli were observed between microstructures, bulk material, and nanowires with radii of 20,300,nm. Microstructure, morphological undulation, defects, and contaminations, however, can drastically change the apparent Young's moduli of nanowires. Examples are given, where an apparent increasing or decreasing of the Young's modulus with decreasing diameter is caused by such effects. The same effects have also influence on the fracture strength in nanowires. While perfect Au nanowires exhibit fracture strengths exceeding the bulk values up to two orders of magnitude, any anomaly causes earlier failure. In addition, failure mechanisms are observed to be dependent on the microstructure. While single crystalline Au nanowires have shown a pure elastic deformation upon load, polycrystalline nanowires show a remarkable plastic deformation before breaking. [source] Mg-doped InN and InGaN , Photoluminescence, capacitance,voltage and thermopower measurementsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2008J. W. Ager III Abstract The bandgap range of InGaN extends from the near-IR (InN, 0.65 eV) to the ultraviolet. To exploit this wide tuning range in light generation and conversion applications, pn junctions are required. The large electron affinity of InN (5.8 eV) leads to preferential formation of native donor defects, resulting in excess electron concentration in the bulk and at surfaces and interfaces. This creates difficulties for p-type doping and/or measuring of the bulk p-type activity. Capacitance,voltage measurements, which deplete the n-type surface inversion layer, have been used to show that Mg is an active acceptor in InN and Inx Ga1,xN for 0.2 < x < 1.0, i.e. over the entire composition range. Mg acceptors can be compensated by irradiation-induced native donors. Thermopower measurements were used to provide definitive evidence that Mg-doped InN has mobile holes between 200 K and 300 K. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Unintentionally doped InN grown onto an atomically flat AlN intermediate layer using plasma-assisted molecular beam epitaxyPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006K. R. Wang Abstract Unintentionally doped InN has been grown onto an atomically flat AlN intermediate layer on top of the Si(111) substrate using plasma-assisted molecular beam epitaxy (PA-MBE). Though there are lots of micrometer-size indium droplets randomly distributed on the top of the surface, the highest electron mobility of this InN thin film measured at room temperature by van der Pauw method is still higher than 1000 cm2/V s with a carrier concentration of 5,8.9 × 1018 cm,3. A symmetrical X-ray rocking curve is measured and the full-width-at-half-maximum (FWHM) of this sample is 1089 arcsec. In the meantime, the threading dislocation (TD) density of this material is estimated to around 9.8 × 108 cm,2 , 7.5 × 109 cm,2 depending on the probing regions that are studied by the etching technique and field-emission scanning electron microscopy (FE-SEM). (2 × 1) in situ reflection high-energy electron diffraction (RHEED) patterns show that this sample is grown under In-rich environment with possible In-terminated surface. From the FE-SEM pictures which were taken from the samples after 10 minutes etching in hydrochloride, the surface morphology shows In-polarity-like patterns that coincide with those procured in RHEED. To select and grow a high-quality laminated AlN as intermediate layer is believed to be the major step in obtaining this high electron mobility InN thin film on Si substrate. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Generalized Wannier functions: An efficient way to construct ab-initio tight-binding parameters for group-III nitridesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006M. Wahn Abstract An ab-initio tight-binding (TB) parametrization has successfully been accomplished for the group-III nitrides GaN and InN as well as for GaAs. The approach allows for multi-scale electronic structure calculations while conserving the accuracy of the atomic scale. The method has been implemented into the plane-wave pseudopotential code S/PHI/nX (http://www.sfhingx.de [1]). Based on it we have performed careful checks of the efficiency (number of non-vanishing matrix elements of the TB Hamiltonian) and the accuracy (description of the bandstructure in comparison to the plane-wave basis). The effect of different exchange-correlation functionals (LDA, EXX) has also been investigated. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Properties of the fundamental absorption edge of InN crystals investigated by optical reflection and transmission spectraPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2004Y. Ishitani Abstract InN crystals are grown on sapphire substrates using a plasma-assisted MBE system. The carrier concentrations of the samples are 2 × 1018,1 × 1019 cm,3. Optical transmission and reflectance measurements are performed on these samples in the temperature range 5,300 K. The resultant spectra are analysed by theoretical spectra based on the LO-phonon,plasmon coupling scheme for the phonon-related factor and non-parabolic conduction band structure for the electronic transition factor. The observed absorption edge is estimated to originate from a valence band to conduction band transition rather than a defect- or impurity-related transition. It is estimated that InN has a bandgap energy in the range 0.59,0.65 eV. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effective mass of InN estimated by Raman scatteringPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010Jung Gon Kim Abstract We have estimated the longitudinal effective mass (m,) of electron in n-type InN films by Raman scattering. The samples were grown by MOVPE (metal organic vapor phase epitaxy) with free carrier concentration of n =6.7×1018 -9.9×1018 cm -3 according to Hall measurement. A weak Raman signal observed at ,430 cm -1 at room temperature was sharpened and shifted to higher frequency toward the A1(TO)-phonon mode at 447 cm -1 with increasing n. This mode was assigned to the lower branch (L - ) of the longitudinal-optic-phonon-plasmon-coupled (LOPC) mode. The line shape was carefully analyzed by a semi-classical line-shape fitting analysis assuming deformation potential and electro-optic coupling mechanisms for the light scattering process. A line-shape fitting analysis was conducted by adjusting three major parameters; electron density, effective mass and plasmon damping rate. The analysis well reproduced values of electron density and mobility deduced by Hall measurement. Electron effective mass of m,*/m0 = 0.05 (±0.01) was also obtained as the best-fit parameter. The result agrees well with previous data obtained by other optical methods. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] RF-MBE growth of InN on 4H-SiC (0001) with off-anglesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010Misao Orihara Abstract We have grown InN on 4H-SiC (0001) substrates with various off-angles by RF-N2 plasma molecular beam epitaxy (RF-MBE). Scanning electron microscope observation revealed that InN films grown on 4H-SiC (0001) substrates with off-angles of 4° and 8° are very smooth and that there are no voids which have often observed for InN epitaxial layers. X-ray diffraction reciprocal space maps for InN grown on 4H-SiC (0001) showed that the c-axes of InN grown on 4H-SiC 4° and 8° off substrates are inclined by 0.35° and 0.8°, respectively, toward the misorientation of the substrate while the c-axis of InN is parallel to that of 4H-SiC for the on-axis substrate. Strong PL peak was observed from InN grown on 4° off substrate at 0.68 eV at 15 K. The PL peak was clearly observed even at room temperature and simply shifted to lower energies with increasing temperature. The difference in the PL peak energy between at 15 K and 300 K was 20 meV, which is reasonable taking into account the difference in the thermal coefficients of InN and SiC (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Natural oxidation of InN quantum dots: the role of cubic InNPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2010David González Abstract The natural aging process occured in indium nitride quantum dots (QDs) heterostructures as a consequence of exposure to the atmosphere has been studied by means of transmission electron microscopy and electron beam related techniques. The comparison between GaN-capped and uncapped InN QDs kept at room conditions during 36 months indicates the structural changes that take place. While the capping layer seems to act in a protective way avoiding any change in the QDs, the uncapped structures suffer a series of phase transformations, where the original wurtzite structure is replaced by a layer of cubic phases. The main constituent of this layer is shown to be bcc-In2O3 formed by the substitution of the nitrogen atoms by oxygen from the atmosphere. This supposes a transformation from a hexagonal to a cubic structure, explained by the existence of an oxygen-rich cubic InN acting as an intermediate phase. The difference in the formation enthalpy between the original and the final product, together with the good match between the crystals would explain this transformation that shows the high instability of InN at environmental conditions. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Investigation of polarity dependent InN{0001} decomposition in N2 and H2 ambientPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009R. Togashi Abstract The polarity dependence of decomposition of the (0001) In- and (000) N-polarity InN layers grown by hydride vapor phase epitaxy (HVPE) on freestanding GaN substrates was investigated. In flowing N2, In- and N-polarity InN layers start to decompose over 550 and 610 °C, respectively. Therefore, the N-polarity InN layer is more stable than the In-polarity InN layer. On the other hand, in flowing H2, InN layers of both polarities start to react with H2 at a low temperature of 350 °C leaving In droplets on the surfaces. Further more, the decomposition rate of the N-polarity InN layer is larger than that of the In-polarity InN layer below approximately 450 °C, while the decomposition rate of the In-polarity InN layer is larger than that of the N-polarity InN above 450 °C. An Arrhenius plot of the decomposition rates revealed that the activation energies, EA, for the decomposition reactions of In- and N- polarity InN layers are 168 and 107 kJ/mol, respectively, which are much smaller than that for GaN and AlN decomposition. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] TEM characterization of M -plane InN grown on (100) LiAlO2 substrate by RF-MBEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009Hirokazu Nozawa Abstract In this study, we characterized the microstructure of M -plane InN using transmission electron microscopy (TEM). The M -plane InN was grown on a (100) LiAlO2 substrate using radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE). We determined the epitaxial relationships of the M -plane InN and LiAlO2 using selected area electron diffraction (SAED). The epitaxial relationships were exactly the same as the M -plane GaN grown on the same substrate. Also, the M -plane InN was grown on the (100) LiAlO2 despite the high lattice mismatches between M -plane InN and LiAlO2. We observed a high density of stacking faults parallel to (0001)InN. The density was estimated about 1.8×106 cm,1, which was one order of magnitude higher than that of non-polar GaN. The correlation between threading dislocations and stacking faults is investigated. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Conduction band filling in In-rich InGaN and InN under hydrostatic pressurePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008G. Franssen Abstract We demonstrate the effect of conduction band shape evolution of InGaN with increasing In content and applying hydrostatic pressure. The influence of conduction band filling on the hydrostatic pressure dependence of photoluminescence in In0.7Ga0.3N and InN is investigated. It is found that the PL pressure coefficient dEPL/dp of InN changes from ,27 meV/GPa to ,21 meV/GPa when the electron concentration increases from 3.6×1017 cm,3 to 1.1×1019 cm,3. In contrast, no significant change of dEPL/dp with electron concentration was observed for In0.7Ga0.3N. We conclude that the pressure sensitivity of the Fermi level, which is responsible for the lowering of dEPL/dp with respect to dEG/dp in InN, is much less prominent in In0.7Ga0.3N than in InN. We attribute this difference to the larger band gap of In0.7Ga0.3N, which lowers the pressure sensitivity of m*. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Atmospheric-pressure MOVPE growth of In-rich InAlNPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008Y. Houchin Abstract This paper reports the atmospheric-pressure MOVPE growth of In-rich InAlN. All InAlN films prepared here (Al content:0, 0.43) do not show phase separation. The incorporation of Al in InAlN is decreased with increasing growth temperature. A decrease in Al content is also observed for films grown at a position farther from the up-stream end of the susceptor. The marked decrease in the Al content along the gas flow direction seems to be caused by the shortage of TMA supply at the downstream by the parasitic reaction of TMA. A single-crystalline InAlN film with an Al content of 0-0.43 is successfully grown by adjusting growth temperature and TMA/(TMI+TMA) molar ratio. FWHM of X-ray rocking curve for InAlN is increased with increasing Al content. The carrier concentrations in InAlN films are comparable to that in InN (1-5 × 1019 cm,3). All the single-crystalline InAlN films with an Al content of 0-0.3 show a photoluminescence at room temperature. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||