TY - GEN A1 - Steuer, O. A1 - Liedke, Maciej O. A1 - Butterling, M. A1 - Schwarz, D. A1 - Schulze, J. A1 - Li, Z. A1 - Wagner, A. A1 - Fischer, Inga Anita A1 - Hübner, R. A1 - Zhou, S. T1 - Evolution of point defects in pulsed-laser-melted Ge1-xSnx probed by positron annihilation lifetime spectroscopy T2 - Journal of Physics: Condensed Matter N2 - Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy grown Ge1-xSnx films treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening – variable energy positron annihilation spectroscopy and variable energy positron annihilation lifetime spectroscopy are used to investigate the defect nanostructure in the Ge1-xSnx films exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, the positron annihilation spectroscopy analysis provides information about dislocations and Ge vacancies decorated by Sn atoms. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters. KW - GeSn KW - laser annealing KW - positron annihilation KW - PLM KW - point defects Y1 - 2023 UR - https://iopscience.iop.org/article/10.1088/1361-648X/ad0a10/meta U6 - https://doi.org/10.1088/1361-648X/ad0a10 SN - 0953-8984 VL - 36 IS - 8 SP - 1 EP - 11 ER - TY - GEN A1 - Dropco, Ivor A1 - Kaiser, Ulrich A1 - Wagner, Lola A1 - Brunner, Stefan M. A1 - Schlitt, Hans Jürgen A1 - Stroszczynski, Christian A1 - Jung, Friedrich A1 - Yi, Dong A1 - Herr, Wolfgang A1 - Jung, Ernst Michael T1 - Color mapping using ultrasound system-integrated perfusion software for evaluation of focal liver lesions: a possible first step for more independent reading T2 - Journal of Gastrointestinal and Liver Diseases N2 - Aims To assess the value of using integrated parametric ultrasound software for contrast-enhanced ultrasonography (CEUS) of liver tumors. Methods 107 patients with liver tumors were studied. CEUS were performed to detect focal lesions. Parametric images were based on continuous CINE LOOPs, from the early-arterial phase (15 s) to the portal-venous phase (1 min) generated by perfusion software. The evaluations of the parametric images and their dignity for liver lesions were performed independently by an experienced and a less-experienced investigator. Computed tomography, magnetic resonance imaging scans or histological analysis were used as references. Results High parametric image quality were obtained in all patients. Among the patients, 44% lesions were benign, 56% were malignant. The experienced investigator correctly classified 46 of 47 (98%) as benign, and 60 of 60 (100%) as malignant tumors based on the parametric images. The less-experienced investigator correctly classified 39 of 47 (83%) as benign, and 49 of 60 (82%) malignant tumors, acheaving a high statistical accuracy of 98% with this type of diagnostic. Conclusion Parametric imaging for grading the malignant degree of tumor may be a good complement to existing ultrasound techniques and was particularly helpful for improving the assessments of the less-experienced examiner. KW - CEUS KW - parametric imaging KW - dynamic vascularization KW - liver malignancies Y1 - 2023 UR - https://europepmc.org/article/med/38147619 U6 - https://doi.org/10.15403/jgld-4997 SN - 1842-1121 VL - 32 IS - 4 SP - 479 EP - 487 ER -