Search Results - "Wellmann, P."

In situ X-ray monitoring of transport and chemistry of Ga-containing intermediates under ammonothermal growth conditions of GaN by Schimmel, S., Duchstein, P., Steigerwald, T.G., Kimmel, A.-C.L., Schlücker, E., Zahn, D., Niewa, R., Wellmann, P.

“…•Evaluation of face-selectivity of ammonothermal etching by in situ X-ray imaging.•Visualization of transport of Ga-transporting species by in situ X-ray…”
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Light extraction from OLEDs for lighting applications through light scattering by Bathelt, R., Buchhauser, D., Gärditz, C., Paetzold, R., Wellmann, P.

“…OLEDs are gaining increasing interest for lighting applications as large-area light sources. Their lifetime and overall efficiency can be increased by the…”
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Tuning the Properties of CZTS Films by Controlling the Process Parameters in Cost-Effective Non-vacuum Technique by Abdelhaleem, Soraya, Hassanien, A. E., Ahmad, Rameez, Schuster, Matthias, Ashour, A. H., Distaso, Monica, Peukert, Wolfgang, Wellmann, P. J.

“…Highly dispersive Cu 2 ZnSnS 4 (CZTS) nanoparticles were successfully synthesized by a simple solvothermal route. A low cost, non-vacuum method was used to…”
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Impacts of carrier capture processes in the thermal quenching of photoluminescence in Al–N co-doped SiC by Tarekegne, Abebe T., Norrman, K., Jokubavicius, V., Syväjärvi, M., Schuh, P., Wellmann, P., Ou, H.

“…High concentrations of aluminum (Al) and nitrogen (N) dopants of 6H SiC have been achieved by a fast sublimation growth process. The Al–N co-doped 6H-SiC layer…”
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Growing bulk‐like 3C‐SiC from seeding material produced by CVD by Schuh, P., Arzig, M., Litrico, G., La Via, F., Mauceri, M., Wellmann, P. J.

“…We present a process to transfer CVD grown heteroepitaxial 3C‐SiC on Si onto polycrystalline SiC, involving an etching step to get rid of the Si and a…”
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Dependence of the seed layer quality on different temperature ramp-up conditions for 3C-SiC hetero-epitaxy on Si (100) by Hens, P., Wagner, G., Hölzing, A., Hock, R., Wellmann, P.

“…Usually a waiting step at around 1000°C to 1100°C is implemented during the carbonization for 3C-SiC epitaxy on silicon in order to form a closed carbon layer…”
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Effects of source material on epitaxial growth of fluorescent SiC by Jokubavicius, V., Hens, P., Liljedahl, R., Sun, J.W., Kaiser, M., Wellmann, P., Sano, S., Yakimova, R., Kamiyama, S., Syväjärvi, M.

“…The growth of fluorescent SiC using Fast Sublimation Growth Process was demonstrated using different types of SiC source materials. These were prepared by (i)…”
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Optimization of KOH etching parameters for quantitative defect recognition in n- and p-type doped SiC by Sakwe, S.A., Müller, R., Wellmann, P.J.

“…We have developed a KOH-based defect etching procedure for silicon carbide (SiC), which comprises in situ temperature measurement and control of melt…”
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Scanning electron microscopical examination of the impact of laser patterning on microscopic inhomogeneities of Cu(In,Ga)(Se,S)2 absorbers produced by rapid thermal processing by Künecke, U., Hölzing, A., Jost, S., Lechner, R., Vogt, H., Heiβ, A., Palm, J., Hock, R., Wellmann, P.

“…Laser scribing of the Mo back electrode is commonly applied to define the cell structure of Cu(In,Ga)(Se,S)2 (CIGSSe) thin film solar cells. The patterning…”
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The influence of gallium on phase transitions during the crystallisation of thin film absorber materials Cu(In,Ga)(S,Se) 2 investigated by in-situ X-ray diffraction by Hölzing, A., Schurr, R., Jost, S., Palm, J., Deseler, K., Wellmann, P., Hock, R.

“…Chalcopyrite based photovoltaic materials Cu(In xGa 1 − x )(S ySe 1 − y ) 2 (CIGSSe) are substituted in the cation and anion lattice to adopt the semiconductor…”
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Numerical modeling and experimental verification of modified-PVT crystal growth of SiC by Wellmann, P.J., Pons, M.

“…This work focuses on numerical modeling of temperature field and mass transport in a so-called modified physical vapor transport (M-PVT) growth configuration,…”
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Sublimation growth of bulk 3C-SiC using 3C-SiC-on-Si (100) seeding layers by Schuh, P., Schöler, M., Wilhelm, M., Syväjärvi, M., Litrico, G., La Via, F., Mauceri, M., Wellmann, P.J.

“…•A transfer of high quality 3C-SiC-on-Si to 3C-SiC-on-SiC was developed.•A subsequent growth of the transferred seeds was conducted.•Layers of up to 850μm…”
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Vapor growth of SiC bulk crystals and its challenge of doping by Wellmann, P.J., Müller, R., Queren, D., Sakwe, S.A., Pons, M.

“…The paper reviews the so-called Modified-PVT (M-PVT) technique which combines the state of the art PVT technique for SiC crystal growth with physical and…”
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Fluorescent SiC as a new material for white LEDs by Syväjärvi, M, Müller, J, Sun, JW, Grivickas, V, Ou, Y, Jokubavicius, V, Hens, P, Kaisr, M, Ariyawong, K, Gulbinas, K, Liljedahl, R, Linnarsson, M K, Kamiyama, S, Wellmann, P, Spiecker, E, Ou, H

“…Current III-V-based white light-emitting diodes (LEDs) are available. However, their yellow phosphor converter is not efficient at high currents and includes…”
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Sublimation growth of thick freestanding 3C-SiC using CVD-templates on silicon as seeds by Hens, P., Jokubavicius, V., Liljedahl, R., Wagner, G., Yakimova, R., Wellmann, P., Syväjärvi, M.

“…Cubic silicon carbide is a promising material for medium power electronics operating at high frequencies and for the subsequent growth of gallium nitride for…”
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Influence of the starting materials used in the crystal growth process of CZT for gamma ray radiation applications by Zheng, Q., Crocco, J., Bensalah, H., Wellmann, P., Osvet, A., Künecke, U., Dierre, F., Vela, O., Perez, J.M., Dieguez, E.

“…The influences of two different ways of crystal growth preparations by using different starting materials on the detector properties have been investigated…”
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The influence of microstructure on the magnetic properties of WC/Co hardmetals by Topić, I., Sockel, H.G., Wellmann, P., Göken, M.

“…The magnetic properties of conventional and ultrafine-grained WC/Co hardmetals have been measured and related to the microstructure. The microstructure was…”
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Determination of charge carrier concentration in n - and p -doped SiC based on optical absorption measurements by Weingärtner, R., Wellmann, P. J., Bickermann, M., Hofmann, D., Straubinger, T. L., Winnacker, A.

“…We have investigated the effect of doping on absorption for various SiC polytypes, i.e., n-type (N) 6H–SiC, 4H–SiC, and 15R–SiC, p-type (Al) 6H–SiC, and…”
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Determination of doping levels and their distribution in SiC by optical techniques by Wellmann, P.J., Weingärtner, R.

“…We review an absorption measurement based characterization method for the determination of doping levels and doping level distribution in SiC which is…”
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Aluminum p-type doping of silicon carbide crystals using a modified physical vapor transport growth method by Straubinger, T.L., Bickermann, M., Weingärtner, R., Wellmann, P.J., Winnacker, A.

“…We report the development of a modified physical vapor transport (PVT) growth setup for the improved aluminum p-type doping of silicon carbide (SiC) single…”
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