@inproceedings{RudolphLenkDoerneretal., author = {Rudolph, Matthias and Lenk, Friedrich and D{\"o}rner, Ralf and Heymann, Peter}, title = {Influence of 2 GHz Harmonic Load-Pull on HBT and MESFET Output Power and Efficiency}, series = {1999 IEEE MTT-S International Microwave Symposium digest, June 13 - 19, 1999, Anaheim Convention Center, Anaheim, California}, booktitle = {1999 IEEE MTT-S International Microwave Symposium digest, June 13 - 19, 1999, Anaheim Convention Center, Anaheim, California}, publisher = {Piscataway, NJ}, address = {IEEE}, isbn = {0-7803-5135-5}, pages = {741 -- 744}, language = {en} } @inproceedings{RudolphDoernerHeymannetal., author = {Rudolph, Matthias and D{\"o}rner, Ralf and Heymann, Peter and Lenk, Friedrich}, title = {Modeling of Low-Frequency Noise in GaInP/GaAs Hetero-Bipolar-Transistors}, series = {2001 IEEE MTT-S International Microwave Symposium digest, May 20 - 25, 2001, Phoenix Civic Plaza, Phoenix, AZ, 1967 - 1970, Vol.3}, booktitle = {2001 IEEE MTT-S International Microwave Symposium digest, May 20 - 25, 2001, Phoenix Civic Plaza, Phoenix, AZ, 1967 - 1970, Vol.3}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {0-7803-6538-0}, pages = {1967 -- 1970}, language = {en} } @inproceedings{LenkRudolph, author = {Lenk, Friedrich and Rudolph, Matthias}, title = {New Extraction Algorithm for GaAs-HBTs With Low Intrinsic Base Resistance}, series = {IEEE MTT-S International Microwave Symposium digest, June 2 - 7, 2002, Washington State Convention \& Trade Center, Seattle, Washington, Vol. 2}, booktitle = {IEEE MTT-S International Microwave Symposium digest, June 2 - 7, 2002, Washington State Convention \& Trade Center, Seattle, Washington, Vol. 2}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {0-7803-7239-5}, pages = {725 -- 728}, language = {en} } @inproceedings{RudolphLenkDoerneretal., author = {Rudolph, Matthias and Lenk, Friedrich and D{\"o}rner, Ralf and Heymann, Peter}, title = {Towards a Unified Method to Implement Transit-Time Effects in Pi-Topology HBT CompactModels}, series = {IEEE MTT-S International Microwave Symposium digest, June 2 - 7, 2002, Washington State Convention \& Trade Center, Seattle, Washington, Vol. 2}, booktitle = {IEEE MTT-S International Microwave Symposium digest, June 2 - 7, 2002, Washington State Convention \& Trade Center, Seattle, Washington, Vol. 2}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {0-7803-7239-5}, pages = {997 -- 1000}, language = {en} } @misc{RudolphLenkLlopisetal., author = {Rudolph, Matthias and Lenk, Friedrich and Llopis, O. and Heinrich, Wolfgang}, title = {On the Simulation of Low-Frequency Noise Upconversion in InGaP/GaAs HBTs}, series = {IEEE transactions on microwave theory and techniques}, volume = {54}, journal = {IEEE transactions on microwave theory and techniques}, number = {7}, issn = {0018-9480}, pages = {2954 -- 2961}, language = {en} } @misc{LenkSchottHilsenbecketal., author = {Lenk, Friedrich and Schott, Matthias and Hilsenbeck, Jochen and Heinrich, Wolfgang}, title = {A new design approach for low phase-noise reflection-type MMIC oscillators}, series = {IEEE transactions on microwave theory and techniques}, volume = {52}, journal = {IEEE transactions on microwave theory and techniques}, number = {12}, issn = {0018-9480}, doi = {10.1109/TMTT.2004.837319}, pages = {2725 -- 2731}, abstract = {In this paper, optimization of the loaded quality factor QL for reflection-type heterojunction bipolar transistor (HBT) oscillators is investigated. The main result is an optimum relation between the S-parameter phases at the three transistor ports. A new design strategy for this type of oscillator is proposed. The analysis is verified by comparing several Ka-band monolithic-microwave integrated-circuit oscillators in GaAs HBT technology with different resonators. The measured loaded QL values correspond to the measured phase noise of the circuits. At an oscillation frequency of 33 GHz, an excellent phase noise of -87 dBc/Hz at 100-kHz offset frequency is achieved over the whole tuning range.}, language = {en} } @inproceedings{RichterFriedrichPhilipetal., author = {Richter, Matthias and Friedrich, Daniel and Philip, Shine and Paloumpa, Ioanna and M{\"u}ller, Klaus and Schmeißer, Dieter}, title = {Study of P3HT/PCBM based films by NEXAFS}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 194}, abstract = {In this contribution we report on investigations of the electronic structure and composition of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) based films by using Near Edge X-Ray Absorption Fine Structure (NEXAFS). The measurements were done at the U49/2-PGM2 beam line of BESSY II, Berlin using TEY (total electron yield) and TFY (total fluorescence yield) detection. The samples were produced by spin casting a mixture of P3HT (dissolved in chloroform) and PCBM (dissolved in chlorobenzene) on ITO (indium tin oxide) coated glass slides. Measurements of pure P3HT and PCBM show all typical excitations, whereas the blended system is a weighted superposition of the related peaks. Analyzing these weighted superposition, we observe in the surface sensitive TEY data an accumulation of P3HT, whereas in the bulk sensitive TFY signal an as expected mixture is found. We also show angular dependent NEXAFS measurements of the P3HT/PCBM blend in order to measure the orientation and distribution of the P3HT polymer. Additionally, we will show a new approach for organic solar cell application by introducing ferroelectric nanoparticles into the mixture.}, language = {en} } @misc{ZaussingerKupkaEgbersetal., author = {Zaussinger, Florian and Kupka, Friedrich and Egbers, Christoph and Neben, Matthias and H{\"u}cker, S. and Bahr, C. and Schmitt, M.}, title = {Semi-convective layer formation}, series = {Journal of Physics: Conference Series}, volume = {837}, journal = {Journal of Physics: Conference Series}, number = {1}, doi = {10.1088/1742-6596/837/1/012012}, pages = {7}, language = {en} } @misc{WernerZidekKammereretal., author = {Werner, Jens Martin and Zidek, Martin and Kammerer, Sylvia and Platz Batista da Silva, Natascha and Jung, Friedrich and Schlitt, Hans J{\"u}rgen and Hornung, Matthias and Jung, Ernst Michael}, title = {Intraoperative contrast-enhanced ultrasound can have a crucial role in surgical decision-making during hepato-pancreatico-biliary surgery -Analysis of impact and input}, series = {Clinical Hemorheology and Microcirculation}, volume = {78}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, doi = {10.3233/CH-201031}, pages = {1 -- 14}, abstract = {OBJECTIVE: To assess the impact and procedural input of intraoperative ultrasound (IOUS) with contrast-enhanced ultrasound (CEUS) and ultrasound elastography on surgical decision making during the procedure and consequently the out-come after hepato-pancreatico-biliary (HPB) surgery. MATERIALS AND METHODS: Data of 50 consecutive patients, who underwent HPB surgery from 04/2018 to 07/2018 were prospectively collected for this study. During surgery, IOUS with a high-resolution ultrasound device using CEUS after bolus injection of 2.4-5 ml Sulphur hexafluoride microbubbles using a 6-9 MHz probe and a share wave and strain elastography was performed by an experienced examiner. Process and time analysis were carried out using mobile phone timer. RESULTS: The IOUS with CEUS and elastography correctly identified 42 malignant tumors and 4 benign lesions. In 3 cases, the examination provided false positive result (identifying 3 benign lesions as malignant) and in 1 case a malignant lesion was incorrectly assessed as benign (sensitivity 97,7\%, specificity 57,1\%, PPV 93,3\% and NPV 80\%). The specific question by the surgeon could be answered successfully in 98\% of the cases. In 76\% of the cases, there was a modification (42\%) or a fundamental change (34\%) of the planned surgical approach due to the information provided by the IOUS. Within the last group, the IOUS had a major impact on therapy outcome. In 7 patients an additional tumor resection was required, in 5 patients the tumor was assessed as inoperable, and in total in 5 patients an intraoperative RFA (4/5) or postoperative RITA (1/5) was required. Regarding procedural input, there was only a slight, but significant difference between the transport and set-up times before the intraoperative use (mean: 14 min 22 s) and the return transport (mean 13 min 6 s), (p = 0,038). The average examination time was 14 minutes, which makes only one third of the overall time demand. CONCLUSION: Combination of IOUS with CEUS and elastography in oncological HPB surgery provides valuable information that affects surgical decision-making. The procedural input of about 45 minutes seems to be a good investment considering the improvement of the surgical procedure and a significant modification of the therapy approach in the majority of the cases.}, language = {en} } @misc{TolksdorfKaiserPetretal., author = {Tolksdorf, Johann Friedrich and Kaiser, Knut and Petr, Libor and Herbig, Christoph and Koč{\´a}r, Petr and Heinrich, Susann and Wilke, Franziska D.H. and Theuerkauf, Martin and F{\"u}lling, Alexander and Schubert, Matthias and Schr{\"o}der, Frank and Křiv{\´a}nek, Roman and Schulz, Lars and Bonhage, Alexander and Hemker, Christiane}, title = {Past human impact in a mountain forest: geoarchaeology of a medieval glass production and charcoal hearth site in the Erzgebirge, Germany}, series = {Regional Environmental Change}, volume = {20}, journal = {Regional Environmental Change}, number = {3}, issn = {1436-378X}, doi = {10.1007/s10113-020-01638-1}, pages = {20}, language = {en} } @misc{MeyerBorislavovEckertetal., author = {Meyer, Werner and Borislavov, Borislav and Eckert, Friedrich and Richter, Christian and R{\"o}mer, Ronald and Beim Graben, Peter and Huber, Markus and Wolff, Matthias}, title = {Formalisierung und Implementierung einer adaptiven kognitiven Architektur unter Verwendung von Strukturdiagrammen}, series = {Elektronische Sprachsignalverarbeitung 2021 : Tagungsband der 32. Konferenz Berlin, 3.-5. M{\"a}rz 2021}, journal = {Elektronische Sprachsignalverarbeitung 2021 : Tagungsband der 32. Konferenz Berlin, 3.-5. M{\"a}rz 2021}, editor = {Hillmann, Stefan and Weiss, Benjamin and Michael, Thilo and M{\"o}ller, Sebastian}, publisher = {TUDpress}, address = {Dresden}, isbn = {978-3-959082-27-3}, issn = {0940-6832}, pages = {67 -- 76}, abstract = {Das Fachgebiet der Kognitiven Technischen Systeme zeichnet sich durch einen hohen Grad an Interdisziplinarit{\"a}t (z. B. Kenntnisse auf den Gebieten Biologie, Psychologie, Informatik und den Ingenieurwissenschaften) aus. Nach wie vor besteht Bedarf an einer methodischen Darstellung des Fachgebietes, bei der die theoretische Durchdringung von Zusammenh{\"a}ngen zwischen den verschiedenen Wissensgebieten zus{\"a}tzlich durch Anschaulichkeit unterst{\"u}tzt wird. Die vorliegende Arbeit stellt einen Fortschrittsbericht zur Realisierung eines Forschungs- und Experimentiersystems dar, mit dem wir dieses Anliegen unterst{\"u}tzen und {\"u}ber das wir erstmals konzeptionell in [1] berichtet haben. In diesem Beitrag folgen wir einem integrativen Ansatz zur Entwicklung einer kognitiven Architektur, mit der unter Verwendung repr{\"a}sentationaler Datenstrukturen adaptives Verhalten auf verschiedenen Zeitskalen sowie zwei wichtige Verhaltensprogramme f{\"u}r das Probleml{\"o}sen (Objektfindung, Exploration) auf der gemeinsamen Grundlage von Markov-Entscheidungsprozessen umgesetzt werden. Mit einem Kurzbericht zum Entwicklungsstand der physikalischen Experimentierumgebung und einer Zusammenfassung der bislang erreichten Ergebnisse beschließen wir den diesj{\"a}hrigen Beitrag.}, language = {de} } @misc{RichterFriedrichSchmeisser, author = {Richter, Matthias and Friedrich, Daniel and Schmeißer, Dieter}, title = {Interlayer-exciton mediated three-hole-Auger-decay in the pi-band of highly oriented pyrolytic graphite}, series = {Physica E}, volume = {Vol. 56}, journal = {Physica E}, issn = {1386-9477}, doi = {10.1016/j.physe.2013.01.015}, pages = {441 -- 446}, abstract = {Resonant photoemission spectroscopy(resPES) is used to probe the occupied pi- and unoccupied pi*-bands of carbon thin films with particular focus on the Auger decay. Highly Oriented Pyrolytic Graphite (HOPG) is studied at the C1s edge. We find strong resonant features at 285.5 eV and 292 eV in the resPES diagram. The normal two-hole Auger decay proceeds under constant kinetic energy (451)only in the sigma*-region. In the pi*-region, however, it proceeds under 67.5° in terms of a Ebind(w) diagram. We attribute this to a multiple Auger decay with a net three hole final state. For this novel decay process we propose a model.We discuss the long lifetime of the first resonant excitation and conclude that it arises from the strong excitonic character of the first resonant state. We use HOPG as a reference system and suggest that this novel process is a tool to identify interlayer-substrate interaction of the carbon layers involved.}, language = {en} } @misc{RichterPaloumpaFriedrichetal., author = {Richter, Matthias and Paloumpa, Ioanna and Friedrich, Daniel and Schmeißer, Dieter}, title = {Multiple Auger Decay At Resonant Photo-Excitation In Carbon Thin Films}, series = {ECS Transactions}, volume = {50}, journal = {ECS Transactions}, number = {20}, doi = {10.1149/05020.0009ecst}, pages = {9 -- 21}, abstract = {We use resonant photoemission at the C1s edge to study the electronic structure of HOPG, graphene flakes and monolayer graphene. We find remarkable differences in the profile of the Auger decay channels, which we attribute to an additional multiple-Auger with a three-hole final state. A prerequisite for the appearance of this decay mechanism is the existence of localized excitonic states, which cause the appearance of the multiple Auger decay. We use those effects to identify the existence and the quantity of such defect states within the π*-band regime in carbon thin films, because the intensity of the three-hole Auger decay is varying with the defect density of the carbon films. We find that the appearance of the multiple Auger decay is different for multilayer and monolayer graphene. In particular the interaction of impurities leads to broadening of the C1s core levels. The three-hole Auger decay spectroscopy is a new method to detect such contaminations with a high sensitivity.}, language = {en} } @misc{RichterFriedrichSchmeisser, author = {Richter, Matthias and Friedrich, Daniel and Schmeißer, Dieter}, title = {Valence and Conduction band states of PCBM as probed by photoelectron spectroscopy at resonant excitation}, series = {BioNanoScience}, volume = {2}, journal = {BioNanoScience}, number = {1}, issn = {2191-1630}, pages = {59 -- 65}, language = {en} } @misc{MuellerRichterFriedrichetal., author = {M{\"u}ller, Klaus and Richter, Matthias and Friedrich, Daniel and Paloumpa, Ioanna and Kramm, Ulrike Ingrid and Schmeißer, Dieter}, title = {Spectroscopic characterization of Cobalt-Phthalocyanine electrocatalysts for fuel cell applications}, series = {Solid State Ionics}, journal = {Solid State Ionics}, number = {216}, issn = {1872-7689}, doi = {10.1016/j.ssi.2011.12.013}, pages = {78 -- 82}, abstract = {For polymer-electrolyte-membrane fuel cells (PEM-FC), platinumcatalysts on carbon based substrates are state of the art, due to high electrochemical activity and chemical stability in acid electrolytes. High costs of platinum force investigations of alternative catalysts. With respect to the oxygen reduction reaction, possible candidates are transition metal (TM) complexes like TM-porphyrines or TM-phthalocyanines. Pyrolysis on carbon based substrates improves the catalytic activity. Highest activities were found for Fe or Co as transition metal centers. We present results of the pyrolysis of Co-phthalocyanine (CoPc) on carbon black. Besides an investigation of morphology by scanning electron microscopy (SEM) and chemical composition by energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) during pyrolysis, we present a near edge X-ray absorption fine structure (NEXAFS) study of the chemical composition for the related annealing steps. This investigation is accompanied by an electrochemical characterization of the catalytic activity and selectivity. The XPS and NEXAFS data indicate a decomposition of the CoN4(chelate-) complex during pyrolysis. The N1s data for 800 °C show graphite-like, formally pyrrolic and pyridinic like features, without any significant contri-bution of Co. The Co2p data for both, XPS and NEXAFS are dominated by CoO/Co2O3. It can be concluded that during the pyrolysis cobalt particles are formed by the disintegration of CoN4-centers, after pyrolysis these par-ticles become oxidized upon contact with air.}, language = {en} } @misc{TallaridaFriedrichStaedteretal., author = {Tallarida, Massimo and Friedrich, Daniel and St{\"a}dter, Matthias and Michling, Marcel and Schmeißer, Dieter}, title = {Growth of TiO2 with Thermal and Plasma Enhanced Atomic Layer Deposition}, series = {Journal of Nanoscience and Nanotechnology}, volume = {11}, journal = {Journal of Nanoscience and Nanotechnology}, number = {9}, issn = {1533-4880}, pages = {8049 -- 8053}, language = {en} } @inproceedings{RichterFriedrichSchmeisser, author = {Richter, Matthias and Friedrich, Daniel and Schmeißer, Dieter}, title = {Multiple Auger decay at resonant photo-excitation in carbon thin films}, series = {Meeting Abstracts-Electrochemical Society, Pacific Rim Meeting on Electrochemical and Solid-State Science, Honolulu, 2012}, booktitle = {Meeting Abstracts-Electrochemical Society, Pacific Rim Meeting on Electrochemical and Solid-State Science, Honolulu, 2012}, publisher = {The Electrochemical Society}, pages = {3509}, language = {en} } @inproceedings{TallaridaMichlingDasetal., author = {Tallarida, Massimo and Michling, Marcel and Das, Chittaranjan and Friedrich, Daniel and St{\"a}dter, Matthias and Schmeißer, Dieter}, title = {Role of substrate chemistry in ALD revealed by in-situ techniques}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 47}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 47}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, abstract = {We show recent results of our in-situ investigations where the role of substrate chemistry in ALD is outlined. While the usual strategy to develop new properties of ALD films is to find new precursors or new procedures, the influence of substrate chemistry on the growth properties of ALD films has been often underestimated. This has principally a technical reason, as the usual characterization methods (QMS, FTIR, ellipsometry) are only weakly sensitive to the substrate, and a characterization of substrates before ALD is often not possible. Thanks to the use of in-situ characterization methods, including photoemission and X-ray absorption spectroscopy with synchrotron radiation, we are able to determine chemical properties of substrates before ALD and after either half or complete ALD cycles. The substrate chemistry influences the standard Al2O3 ALD with TMA and water [1,2], as well as the TiO2 ALD with TTIP and either water, O2 or O2-plasma. [1] M. Tallarida, K. Kukli, M. Michling, M. Ritala, M. Leskel{\"a} and D. Schmeisser, Chem. Mater. 23, 3159 (2011); [2] M. Tallarida, C. Adelmann, A. Delabie, S. van Elshocht, M. Caymax, and D. Schmeisser, Appl. Phys. Lett. 92, 042906 (2011).}, language = {en} } @inproceedings{RichterFriedrichSchmeisser, author = {Richter, Matthias and Friedrich, Daniel and Schmeißer, Dieter}, title = {3h-Auger decay in the π-band of HOPG}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 47}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 47}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, abstract = {In this contribution we report on the electronic structure of highly oriented pyrolitic graphite (HOPG). HOPG is a model system because of the clear separation between π- and σ-bands in the valence band regime. X-ray based measurements were done at the U49/2-PGM2 beam line at BESSYII in Berlin. The resonant photoemission spectra (resPES) at the carbon K-edge give a complete picture of the occupied and unoccupied states in these sp2 hybridized system. Above the K-edge the resPES data are dominated by the Auger process causing a C2p4 final state. The Auger lines appear at constant kinetic energy (spectator, 2h) or constant binding energy (participator, 1h). For the features right at the resonance we observe a different Auger decay mechanism. We attribute it to the decay out of an excitonic intermediate state with a long lifetime. It involves three valence hole states. The original primary core hole is filled by a normal KLL Auger decay. The excited electron rests in the excitonic intermediate state and decays later. We discuss the spectral features of such combined spectator-participator decays in detail which are found only close to resonance and only in the localized valence states of excitonic excitation i.e.C1s - 1π* transitions [1, 2, 3]. [1] Richter et al. (2011) BioNanoScience, submitted. [2] Michling et al. (2011) IOP C Ser Mater Sci Eng, submitted. [3] Schmidt et al. (2011) Solid State Ionics, submitted.}, language = {en} } @inproceedings{TallaridaDessmannStaedteretal., author = {Tallarida, Massimo and Deßmann, Nils and St{\"a}dter, Matthias and Friedrich, Daniel and Michling, Marcel and Schmeißer, Dieter}, title = {Atomic layer deposition of TiO}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 46}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 46}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, abstract = {We present a study of the initial growth of TiO2 on Si(111) by atomic layer deposition (ALD). The Si substrate was etched with NH4F before ALD to remove the native oxide film and to produce a Si-H termination. In-situ experiments by means of photoemission and X-ray absorption spectroscopy were conducted with synchrotron radiation on Ti-oxide films produced using Ti-tetra-iso-propoxide (TTIP) and water as precursors. O1s, Ti2p, C1s, and Si2p core level, and O1s and Ti2p absorption edges show the transition of the Ti-oxide properties during the first layers. The growth starts with a very small growth rate (0.03nm/cycle) due to the growth inhibition of the Si-H termination and proceeds with higher growth rate (0.1nm/cycle) after 1.5nm Ti-oxide has been deposited.}, language = {en} } @misc{FriedrichHenkelRichteretal., author = {Friedrich, Daniel and Henkel, Karsten and Richter, Matthias and Schmeißer, Dieter}, title = {Fullerenol as probed by Synchrotron X-Ray Photoemission and Absorption Spectroscopy}, language = {en} } @inproceedings{PhilipRichterFriedrichetal., author = {Philip, Shine and Richter, Matthias and Friedrich, Daniel and Paloumpa, Ioanna and M{\"u}ller, Klaus and Schmeißer, Dieter}, title = {Spectroscopic investigations of P3HT/PCBM films for organic BHJ solar cells}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 153}, abstract = {Investigations of the electronic structure and composition of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) based films using Near Edge X-Ray Absorption Fine Structure (NEXAFS) are presented. The measurements were performed at the U49/2-PGM2 beam line of BESSY II, Berlin recording TEY (total electron yield) and TFY (total fluorescence yield) data. Samples prepared by spin coating a mixture of P3HT dissolved in chloroform and PCBM dissolved in chlorobenzene onto ITO (indium tin oxide) coated glass slides were analyzed. Upon measuring the pure P3HT and PCBM, all reported excitations were observed, whereas the blended system is a weighted superposition of the related peaks. Analyzing the data we calculate the composition of the mixture. We also show angular dependent NEXAFS measurements of the P3HT/PCBM blend in order to measure the orientation and distribution of the P3HT polymer. Additionally, we show a new approach for organic solar cell application. BaTiO3 nanoparticles were incorporated as nanodispersion into the donor-acceptor blend or the ferroelectric copolymer poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE)) was spincoated as an ultrathin film below the blend.}, language = {en} } @inproceedings{SchottLenkMelianietal., author = {Schott, Matthias and Lenk, Friedrich and Meliani, Chafik and Heinrich, Wolfgang}, title = {Low phase noise X-band push-push oscillator with frequency divider}, series = {2005 IEEE MTT-S International Microwave Symposium, June 12 - 17, 2005, Long Beach, CA}, booktitle = {2005 IEEE MTT-S International Microwave Symposium, June 12 - 17, 2005, Long Beach, CA}, publisher = {IEEE Operations Center}, address = {Piscataway, NJ}, isbn = {0-7803-8845-3}, doi = {10.1109/MWSYM.2005.1516986}, abstract = {A MMIC Colpitts oscillator in push-push configuration with integrated frequency divider using InGaP/GaAs HBTs is presented. The output is taken from the second harmonic port while the fundamental signal is fed to a frequency divider by two thus providing a reference signal at one quarter of the output frequency. The MMIC VCO reaches state-of-the-art phase-noise performance in X-band down to -120dBc/Hz at 1MHz offset frequency at high output power and a tuning range of 4\%.}, language = {en} } @inproceedings{LenkSchottHilsenbecketal., author = {Lenk, Friedrich and Schott, Matthias and Hilsenbeck, Jochen and Heinrich, Wolfgang}, title = {Optimizing MMIC reflection-type oscillators}, series = {2004 IEEE MTT-S International Microwave Symposium digest, June 6 - 11, 2004, Fort Worth Convention Center, Fort Worth, Texas, vol. 3}, booktitle = {2004 IEEE MTT-S International Microwave Symposium digest, June 6 - 11, 2004, Fort Worth Convention Center, Fort Worth, Texas, vol. 3}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {0-7803-8331-1}, doi = {10.1109/MWSYM.2004.1338816}, pages = {1341 -- 1344}, abstract = {In this paper, optimization of the loaded quality factor QL for reflection-type HBT oscillator is investigated. Main result is an optimum relation between the S parameter phases at the three transistor ports. To support this finding, a 35.5 GHz MMIC VCO phase noise better than -85 dBc/Hz at 100 kHz offset frequency is demonstrated.}, language = {en} } @inproceedings{LenkSchottHilsenbecketal., author = {Lenk, Friedrich and Schott, Matthias and Hilsenbeck, Jochen and W{\"u}rfl, Joachim and Heinrich, Wolfgang}, title = {Low phase-noise monolithic GaInP/GaAs-HBT VCO for 77 GHz}, series = {2003 IEEE MTT-S International Microwave Symposium digest, June 8 - 13, 2003, Pennsylvania Convention Center, Philadelphia, Pennsylvania, vol. 2}, booktitle = {2003 IEEE MTT-S International Microwave Symposium digest, June 8 - 13, 2003, Pennsylvania Convention Center, Philadelphia, Pennsylvania, vol. 2}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {0-7803-7695-1}, doi = {10.1109/MWSYM.2003.1212515}, pages = {903 -- 906}, abstract = {Coplanar W-band push-push VCO MMICs using GaInP/GaAs HBTs are presented. One circuit operates at 77 GHz with phase noise of -92 dBc/Hz at 1 MHz offset. To our knowledge this is the first fully monolithic W-band VCO with phase noise better than -90 dBc/Hz. A second version with two varactor diodes yields an almost threefold relative tuning bandwidth.}, language = {en} } @inproceedings{SchottKuhnertLenketal., author = {Schott, Matthias and Kuhnert, Holger and Lenk, Friedrich and Hilsenbeck, Jochen and W{\"u}rfl, Joachim and Heinrich, Wolfgang}, title = {38 GHz push-push GaAs-HBT MMIC oscillator}, series = {2002 IEEE MTT-S International Microwave Symposium digest, June 2 - 7, 2002, Washington State Convention \& Trade Center, Seattle, Washington, vol. 2}, booktitle = {2002 IEEE MTT-S International Microwave Symposium digest, June 2 - 7, 2002, Washington State Convention \& Trade Center, Seattle, Washington, vol. 2}, publisher = {IEEE Service Center}, address = {Piscataway, NJ}, isbn = {0-7803-7239-5}, doi = {10.1109/MWSYM.2002.1011761}, pages = {839 -- 842}, abstract = {Two differential coplanar MMIC HBT oscillators are presented, a fixed frequency and a VCO version. They provide single-ended output at the second harmonic at 38 GHz as well as differential output at 19 GHz. The oscillators show excellent phase noise performance, the fixed-frequency type reaches -95 dBc/Hz at the fundamental frequency and -89 dBc/Hz at the second harmonic, at 100 kHz offset.}, language = {en} } @inproceedings{LenkSchottHeinrich, author = {Lenk, Friedrich and Schott, Matthias and Heinrich, Wolfgang}, title = {Modeling and Measurement of Phase Noise in GaAs HBT Ka-Band Oscillators}, series = {31st European Microwave Conference, 2001, 24 - 26 Sept. 2001}, booktitle = {31st European Microwave Conference, 2001, 24 - 26 Sept. 2001}, publisher = {Microwave Engineering Europe}, address = {London}, doi = {10.1109/EUMA.2001.339168}, pages = {1 -- 4}, abstract = {Accurate oscillator phase-noise simulation is a key problem in MMIC design, which is not solved satisfactory so far and needs further investigation. In this paper, a Ka-band MMIC oscillator with GaInP/GaAs HBT and on-chip resonator is treated as an example. Measured phase noise reaches -90 dBc/Hz and below at 100 kHz offset. To evaluate phase-noise prediction, the circuit is simulated using different commercial simulation tools and HBT models. Considerable differences in simulation results are observed.}, language = {en} } @inproceedings{SchottLenkHeymann, author = {Schott, Matthias and Lenk, Friedrich and Heymann, Peter}, title = {On the load-pull effect in MMIC oscillator measurements}, series = {33rd European Microwave Conference, 7 - 9th October 2003, ICM, Munich, Germany, Vol. 1}, booktitle = {33rd European Microwave Conference, 7 - 9th October 2003, ICM, Munich, Germany, Vol. 1}, publisher = {London}, address = {Korizon House Publ.}, isbn = {1-58053-834-7}, doi = {10.1109/EUMC.2003.1262295}, pages = {367 -- 370}, abstract = {Low phase-noise MMIC oscillators are key components for microwave and nun-wave systems. As a consequence, phase-noise measurements of these circuits have become a subject of growing interest and importance. This paper demonstrates that MMIC oscillator circuits with their relatively low Q factors are prone to specific measurement errors. Caused by a load-pull effect, the measurement system can become part of the oscillator, which yields phase-noise data significantly below reality. Special care has to be taken in order to avoid such phenomena.}, language = {en} } @inproceedings{LenkSchottHilsenbecketal., author = {Lenk, Friedrich and Schott, Matthias and Hilsenbeck, Jochen and Heinrich, Wolfgang}, title = {Low phase-noise GaAs-HBT monolithic W-band oscillator}, series = {34th European Microwave Conference, Tuesday 12th, Wednesday 13th and Thursday 14th October}, booktitle = {34th European Microwave Conference, Tuesday 12th, Wednesday 13th and Thursday 14th October}, publisher = {London}, address = {Horizon House Publ.}, isbn = {1-58053-992-0}, pages = {897 -- 900}, language = {en} } @inproceedings{OsterriederRichterFriedrich, author = {Osterrieder, Peter and Richter, Stefan and Friedrich, Matthias}, title = {Lateral buckling of continuous steel beams with hinges}, language = {en} } @inproceedings{LenkDoernerRumiantsevetal., author = {Lenk, Friedrich and D{\"o}rner, Ralf and Rumiantsev, Andrej and Rudolph, Matthias}, title = {Calibration Residual Error Propagation Analysis Using Conformal Mapping}, series = {77th ARFTG Microwave Measurement Conference (ARFTG 2011), Baltimore, Maryland, USA, 10 June 2011}, booktitle = {77th ARFTG Microwave Measurement Conference (ARFTG 2011), Baltimore, Maryland, USA, 10 June 2011}, publisher = {Piscataway, NJ}, address = {IEEE}, isbn = {978-1-61284-959-1}, pages = {Paper 2-4}, language = {en} }