A. Hölzing

• Dr.rer.nat.
• researcher and group manager at Fraunhofer Institute for Integrated Circuits

The size of 4D tomography datasets acquired at synchrotron or neutron imaging facilities can reach several terabytes, which presents a significant challenge for their evaluation. This paper presents a framework that allows a compressed dataset to be kept in memory and makes it possible to evaluate and manipulate the dataset without requiring enough...

Counterfeit ICs pose a severe risk in terms of reliability and security. Since their identification is very challenging and complex, several well established inspection methods are employed to face this task. So far, two- and three-dimensional X-ray imaging is used to verify structural parameters of the entire IC related to the die (size, orientati...

The local fiber orientation is a micro-structural feature crucial for the mechanical properties of parts made from fiber reinforced polymers. It can be determined from micro-computed tomography data and subsequent quantitative analysis of the resulting 3D images. However, although being by nature non-destructive, this method so far has required to...

The local fiber orientation is a micro-structural feature crucial for the mechanical properties of parts made from fiber reinforced polymers. It can be determined from micro-computed tomography data and subsequent quantitative analysis of the resulting 3D images. However, although being by nature non-destructive, this method so far has required to...

Objective: The purpose of this study was to estimate the feasibility and accuracy of mesio-distal width measurements with magnetic resonance imaging (MRI) in comparison to conventional 3D imaging techniques [multi-slice CT (MSCT), cone-beam CT (CBCT), and µCT]. The measured values of the tooth widths were compared to each other to estimate the amou...

Abstract This work compares two popular MC simulation frameworks ROSI (Roentgen Simulation) and GEANT4 (Geometry and Tracking in its fourth version) in the context of X-ray physics. The comparison will be performed with the help of a parameter study considering energy, material and length variations. While the total deposited energy as well as the...

Objectives: To examine the relative usefulness and suitability of magnetic resonance imaging (MRI) in daily clinical practice as compared to various technologies of computed tomography (CT) in addressing questions of orthodontic interest. Methods: Three blinded raters evaluated 2D slices and 3D reconstructions created from scans of two pig heads...

Stacked elemental layers of Mo/Cu/Sn and Mo/Cu/Sn/Se were employed as samples for investigating the formation reaction of Cu-Sn intermetallic compounds as well as Cu2SnSe3 phases by in situ technique of X-ray diffraction and differential scanning calorimetry. The use of a combined in situ technique allows a real-time observation on solid-state reac...

A combined in-situ investigation using X-ray diffraction and differential scanning calorimetry during annealing was carried out to investigate the formation of intermetallic compounds in the stacked elemental layers and to reveal its influences on the crystallization of kesterite Cu2ZnSnSe4. The Mo/Cu/Zn, Mo/Cu/Sn/Zn, Mo/Cu/Zn/Se and Mo/Cu/Sn/Zn/Se...

Chalkopyrit-basierte Halbleitermaterialien wie Cu(In,Ga)(S,Se)2 werden als Absorber in Dünnschichtsolarzellen verwendet. Sie werden durch schnelle thermische Prozessierung von Schichtpaketen aus den Elementen hergestellt. Um die Effizienz der Umwandlung von Sonnenlicht in elektrischen Strom in Dünnschichtsolarzellen zu verbessern, wird in Chalkopyr...

A self-organized film with titania nanotubular architecture was synthesized by anodization. The dynamic characteristics and kinetic parameters of the nanotubular film during annealing were investigated using real-time resolved, in situ X-ray diffraction (XRD). The XRD results revealed that the onset activation energy for the self-organized titania...

To enhance the conversion efficiency of thin film photovoltaics, chalcopyrite based absorber materials are usually substituted in the cation and anion lattice to yield an absorber with a graded bandgap composed of mixed pentanary crystals Cu(In,Ga)(Se,S)2. Applying in-situ investigations during the crystallisation of the chalcopyrite is a prerequis...

In this work CuInSe2 (CISe) thin films were fabricated by rapid thermal processing of printed CuIn nanoparticles and thermally evaporated selenium as precursor layer. Research is focused on real-time investigations such as in-situ X-ray diffraction and dynamic scanning calorimetry. These measurements show CISe formation starting at 300 °C. Signific...

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 process was performed on laboratory samples using ns and ps pulse length laser processes. After structuring, CIGSSe absorbers were processed by rapid thermal processing (RTP) of stacked elementa...

Cu–Zn–Sn intermetallic thin films were sputtered on Mo-coated soda-lime glass substrates from elemental targets. Samples representing a wide range of compositions around the 2:1:1 kesterite ratio of the Cu–Zn–Sn material system have been investigated. Crystalline phase content and chemical composition of the metal precursors were characterized by X...

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 which prevents the formation of voids by evaporation of Si. On the other hand, such a process step may lead to non-ideal nucleation conditions resulting in a low layer quality with high den...

Chalcopyrite based photovoltaic materials Cu(InxGa1−x)(SySe1−y)2 (CIGSSe) are substituted in the cation and anion lattice to adopt the semiconductor bandgap to the terrestrial solar spectrum. In-situ X-ray diffraction (XRD) investigations on the crystallisation of thin film absorber materials Cu(In,Ga)(S,Se)2 while annealing stacked elemental layer...

The quaternary compound kesterite Cu2ZnSnS4 (CZTS) is a promising candidate for the production of low-cost thin film solar cells.Depending on the precursor composition and deposition technique several intermetallic precursor phases may appear, affecting the formation reactions during the crystallization process of the thin film absorber. A better u...

Sulphurisation of CuInSe2 solar cell absorber materials is of particular interest for band gap engineering by means of compositional grading. We studied the chalcopyrite formation process of Cu–In–S–Se stacks with varying Se to S ratio from 100% Se (0% S) down to 0% Se (100% S). Differential calorimetry (DSC) was applied as a fundamental characteri...

CIS based polycrystalline semiconductors are used for thin film solar cells in laboratory and industry. Nevertheless, even for highly efficient absorbers from different growth techniques, these films are reported to contain inhomogeneities from nanometer to millimeter scale. In this paper we have analyzed inhomogeneities on a sub-μ m scale of CuIn(...

Usually a waiting step at around 1000°C to 1100°C during the carbonization step for 3C-SiC on silicon is implemented for establishing a closed carbon layer to prevent the formation of voids. The latter, however, may lead to non-ideal nucleation conditions for high quality layers with a low density of domain boundaries. Our investigations indicate t...

Thin-film solar cells based on Cu2ZnSnS4 (CZTS) absorbers were fabricated successfully by solid-state reaction in H2S atmosphere of electrodeposited Cu–Zn–Sn precursors. These ternary alloys were deposited in one step from a cyanide-free alkaline electrolyte containing Cu(II), Zn(II) and Sn(IV) metal salts on Mo-coated glass substrates. The solar c...

We present results of in-situ X-ray diffraction experiments on the formation of CuInS2 thin film solar cell absorbers. The experiments have been performed while annealing Cu–In–S stacked elemental layer precursors produced by sputtering and thermal evaporation to investigate the crystallisation process of the chalcopyrite CuInS2. Rietveld refinemen...

The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu2ZnSnS4 based thin film...

To achieve an optimized adaptation of the semiconductor bandgap to the terrestrial solar spectrum, CIS (CuInSe2, CuInS2) based chalcopyrite absorber materials are usually substituted in the cation and anion lattice to yield mixed pentanary crystals with general composition Cu(In,Ga)(Se,S)2. In the past, in-situ XRD (X-ray diffraction) measurements...

CIS based chalcopyrite absorber materials are usually substituted in the cation and anion lattice to yield mixed pentanary crystals with the general composition Cu(In,Ga)(Se,S)2 to achieve an optimised adaptation of the semiconductor bandgap to the terrestrial solar spectrum. Real-time investigations during the annealing of stacked elemental layers...