ORCID Profile
0000-0002-8073-7103
Current Organisations
Friedrich-Schiller-Universität Jena
,
Institut de recherche pour le développement
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Publisher: Elsevier BV
Date: 12-2017
Publisher: AIP Publishing
Date: 05-01-2015
DOI: 10.1063/1.4905347
Abstract: There is particular interest to investigate compositional inhomogeneity of Cu(In,Ga)Se2 solar cell absorbers. We introduce an approach in which focused ion beam prepared thin lamellas of complete solar cell devices are scanned with a highly focused synchrotron X-ray beam. Analyzing the resulting fluorescence radiation ensures high resolution compositional analysis combined with high spatial resolution. Thus, we are able to detect subtle variations of the Ga/(Ga + In) ratio down to 0.01 on a submicrometer scale. We observed that for sequentially processed solar cells a higher selenization temperature leads to absorbers with almost homogenous Ga/(Ga + In) ratio, which significantly improved the conversion efficiency.
Publisher: OSA
Date: 2016
Publisher: Elsevier BV
Date: 12-2021
Publisher: Geological Society of London
Date: 21-06-2010
Publisher: Elsevier BV
Date: 2021
Publisher: IEEE
Date: 05-2013
Publisher: American Vacuum Society
Date: 2009
DOI: 10.1116/1.3043540
Abstract: Single crystalline epitaxial Si(111)/Y2O3(111)/Si(111) heterostructures were grown by molecular beam epitaxy and the morphology, structure, and defects were characterized in detail. The growth of a closed and smooth layer system is demonstrated by means of reflection high energy electron diffraction measurements. X-ray reflectometry and high resolution Rutherford backscattering (RBS) experiments show low surface and interface roughnesses. Channeling RBS as well as x-ray diffraction pole figure studies demonstrate the type A/B/A epitaxy relationship of the Si(111)/Y2O3(111)/Si(111) heterostructure and reveal the existence of defects in the epitaxial Si(111) layer. These defects are studied in detail with high resolution transmission electron microscopy, disclosing microtwin formation and type B Si grains as the major defects.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-06-2022
Abstract: Erbium-doped fiber lifiers revolutionized long-haul optical communications and laser technology. Erbium ions could provide a basis for efficient optical lification in photonic integrated circuits but their use remains impractical as a result of insufficient output power. We demonstrate a photonic integrated circuit–based erbium lifier reaching 145 milliwatts of output power and more than 30 decibels of small-signal gain—on par with commercial fiber lifiers and surpassing state-of-the-art III-V heterogeneously integrated semiconductor lifiers. We apply ion implantation to ultralow–loss silicon nitride (Si 3 N 4 ) photonic integrated circuits, which are able to increase the soliton microcomb output power by 100 times, achieving power requirements for low-noise photonic microwave generation and wavelength- ision multiplexing optical communications. Endowing Si 3 N 4 photonic integrated circuits with gain enables the miniaturization of various fiber-based devices such as high–pulse-energy femtosecond mode-locked lasers.
Publisher: American Chemical Society (ACS)
Date: 11-2018
Abstract: Thin-film solar cells based on Cu(In,Ga)Se
Publisher: Elsevier BV
Date: 11-2021
Publisher: Wiley
Date: 23-02-2017
Publisher: American Chemical Society (ACS)
Date: 11-12-2020
Publisher: Springer Science and Business Media LLC
Date: 28-09-2014
DOI: 10.1038/NPHYS3103
Publisher: Wiley
Date: 22-09-2020
Publisher: Elsevier BV
Date: 05-2020
Publisher: AIP Publishing
Date: 23-01-2017
DOI: 10.1063/1.4974819
Abstract: High-efficiency kesterite-based thin film solar cells typically feature Cu-poor, Zn-rich absorbers although secondary phases occur easily in non-stoichiometric Cu2ZnSnSe4. We therefore applied high-resolution X-ray fluorescence analysis using a synchrotron nanobeam to study the local composition of a CZTSe cross section lamella cut from a s le with an integral composition of Zn/Sn = 1.37 and Cu/(Zn+Sn) = 0.55. We find submicrometer-sized ZnSe-, SnSe/SnSe2-, and even CuSe/Cu2Se-like secondary phases, while the local compositions of the kesterite are highly Zn-rich yet barely Cu-poor with 1.5 ≤ Zn/Sn ≤ 2.2 and Cu/(Zn+Sn) ∼ 1.0. Consequently, great care must be taken when relating the integral composition to other material properties including the device performance.
Publisher: Springer Science and Business Media LLC
Date: 11-05-2023
DOI: 10.1038/S41467-023-38262-6
Abstract: Since Purcell’s seminal report 75 years ago, electromagnetic resonators have been used to control light-matter interactions to make brighter radiation sources and unleash unprecedented control over quantum states of light and matter. Indeed, optical resonators such as microcavities and plasmonic antennas offer excellent control but only over a limited spectral range. Strategies to mutually tune and match emission and resonator frequency are often required, which is intricate and precludes the possibility of enhancing multiple transitions simultaneously. In this letter, we report a strong radiative emission rate enhancement of Er 3+ -ions across the telecommunications C-band in a single plasmonic waveguide based on the Purcell effect. Our gap waveguide uses a reverse nanofocusing approach to efficiently enhance, extract and guide emission from the nanoscale to a photonic waveguide while keeping plasmonic losses at a minimum. Remarkably, the large and broadband Purcell enhancement allows us to resolve Stark-split electric dipole transitions, which are typically only observed under cryogenic conditions. Simultaneous radiative emission enhancement of multiple quantum states is of great interest for photonic quantum networks and on-chip data communications.
Publisher: Wiley
Date: 24-02-2011
Publisher: American Chemical Society (ACS)
Date: 03-12-2019
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Stephanie Brichau.