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- ItemThe HITRAN2020 molecular spectroscopic database(New York, NY [u.a.] : Elsevier, 2022) Gordon, I.E.; Rothman, L.S.; Hargreaves, R.J.; Hashemi, R.; Karlovets, E.V.; Skinner, F.M.; Conway, E.K.; Hill, C.; Kochanov, R.V.; Tan, Y.; Wcisło, P.; Finenko, A.A.; Nelson, K.; Bernath, P.F.; Birk, M.; Boudon, V.; Campargue, A.; Chance, K.V.; Coustenis, A.; Drouin, B.J.; Flaud, J.M.; Gamache, R.R.; Hodges, J.T.; Jacquemart, D.; Mlawer, E.J.; Nikitin, A.V.; Perevalov, V.I.; Rotger, M.; Tennyson, J.; Toon, G.C.; Tran, H.; Tyuterev, V.G.; Adkins, E.M.; Baker, A.; Barbe, A.; Canè, E.; Császár, A.G.; Dudaryonok, A.; Egorov, O.; Fleisher, A.J.; Fleurbaey, H.; Foltynowicz, A.; Furtenbacher, T.; Harrison, J.J.; Hartmann, J.M.; Horneman, V.M.; Huang, X.; Karman, T.; Karns, J.; Kassi, S.; Kleiner, I.; Kofman, V.; Kwabia-Tchana, F.; Lavrentieva, N.N.; Lee, T.J.; Long, D.A.; Lukashevskaya, A.A.; Lyulin, O.M.; Makhnev, V.Yu.; Matt, W.; Massie, S.T.; Melosso, M.; Mikhailenko, S.N.; Mondelain, D.; Müller, H.S.P.; Naumenko, O.V.; Perrin, A.; Polyansky, O.L.; Raddaoui, E.; Raston, P.L.; Reed, Z.D.; Rey, M.; Richard, C.; Tóbiás, R.; Sadiek, I.; Schwenke, D.W.; Starikova, E.; Sung, K.; Tamassia, F.; Tashkun, S.A.; Vander Auwera, J.; Vasilenko, I.A.; Vigasin, A.A.; Villanueva, G.L.; Vispoel, B.; Wagner, G.; Yachmenev, A.; Yurchenko, S.N.The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition.
- ItemEvolution of planar defects during homoepitaxial growth of β-Ga2O3 layers on (100) substrates—A quantitative model(Melville, NY : American Inst. of Physics, 2016) Schewski, R.; Baldini, M.; Irmscher, K.; Fiedler, A.; Markurt, T.; Neuschulz, B.; Remmele, T.; Schulz, T.; Wagner, G.; Galazka, Z.; Albrecht, M.We study the homoepitaxial growth of β-Ga2O3 (100) grown by metal-organic vapour phase as dependent on miscut-angle vs. the c direction. Atomic force microscopy of layers grown on substrates with miscut-angles smaller than 2° reveals the growth proceeding through nucleation and growth of two-dimensional islands. With increasing miscut-angle, step meandering and finally step flow growth take place. While step-flow growth results in layers with high crystalline perfection, independent nucleation of two-dimensional islands causes double positioning on the (100) plane, resulting in twin lamellae and stacking mismatch boundaries. Applying nucleation theory in the mean field approach for vicinal surfaces, we can fit experimentally found values for the density of twin lamellae in epitaxial layers as dependent on the miscut-angle. The model yields a diffusion coefficient for Ga adatoms of D = 7 × 10−9 cm2 s−1 at a growth temperature of 850 °C, two orders of magnitude lower than the values published for GaAs.
- ItemStep-flow growth in homoepitaxy of β-Ga2O3 (100)—The influence of the miscut direction and faceting(Melville, NY : AIP Publ., 2019) Schewski, R.; Lion, K.; Fiedler, A.; Wouters, C.; Popp, K.; Levchenko, S.V.; Schulz, T.; Schmidbauer, M.; Bin Anooz, S.; Grüneberg, R.; Galazka, Z.; Wagner, G.; Irmscher, K.; Scheffler, M.; Draxl, C.; Albrecht, M.We present a systematic study on the influence of the miscut orientation on structural and electronic properties in the homoepitaxial growth on off-oriented β-Ga2O3 (100) substrates by metalorganic chemical vapour phase epitaxy. Layers grown on (100) substrates with 6° miscut toward the [001⎯⎯] direction show high electron mobilities of about 90 cm2 V−1 s−1 at electron concentrations in the range of 1–2 × 1018 cm−3, while layers grown under identical conditions but with 6° miscut toward the [001] direction exhibit low electron mobilities of around 10 cm2 V−1 s−1. By using high-resolution scanning transmission electron microscopy and atomic force microscopy, we find significant differences in the surface morphologies of the substrates after annealing and of the layers in dependence on their miscut direction. While substrates with miscuts toward [001⎯⎯] exhibit monolayer steps terminated by (2⎯⎯01) facets, mainly bilayer steps are found for miscuts toward [001]. Epitaxial growth on both substrates occurs in step-flow mode. However, while layers on substrates with a miscut toward [001⎯⎯] are free of structural defects, those on substrates with a miscut toward [001] are completely twinned with respect to the substrate and show stacking mismatch boundaries. This twinning is promoted at step edges by transformation of the (001)-B facets into (2⎯⎯01) facets. Density functional theory calculations of stoichiometric low index surfaces show that the (2⎯⎯01) facet has the lowest surface energy following the (100) surface. We conclude that facet transformation at the step edges is driven by surface energy minimization for the two kinds of crystallographically inequivalent miscut orientations in the monoclinic lattice of β-Ga2O3.
- ItemGrundlegende Untersuchungen zur Herstellung perfekter, N-dotierter 4H-SiC-Einkristalle hoher Leitfähigkeit und zum Dotierungseinfluss auf den Waferingprozess : Abschlussbericht(Hannover : Technische Informationsbibliothek (TIB), 2003) Siche, D.; Rost, H.-J.; Schulz, D.; Wollweber, J.; Freiberg, A.; Schäbitz, K.; Lux, B.; Wurche, T.; Böttcher, K.; Doerschel, J.; Irmscher, K.; Alex, V.; Wagner, G.[no abstract available]