Rizzi, Angela

[["dc.bibliographiccitation.firstpage","95"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","physica status solidi (RRL) - Rapid Research Letters"],["dc.bibliographiccitation.lastpage","97"],["dc.bibliographiccitation.volume","5"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Martinez-Criado, G."],["dc.contributor.author","Sans, J. A."],["dc.contributor.author","Tucoulou, R."],["dc.contributor.author","Cloetens, P."],["dc.contributor.author","Snigireva, I."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.contributor.author","Rizzi, Angela"],["dc.contributor.author","Gomez-Gomez, M. I."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Cantarero, A."],["dc.date.accessioned","2018-11-07T08:58:39Z"],["dc.date.available","2018-11-07T08:58:39Z"],["dc.date.issued","2011"],["dc.description.abstract","Using synchrotron radiation nanoprobe, this work reports on the elemental distribution in single In(x)Ga(1-x)N nanowires (NWs) grown by molecular beam epitaxy directly on Si(111) substrates. Single NWs dispersed on Al covered sapphire were characterized by nano-X-ray fluorescence, Raman scattering and photoluminescence spectroscopy. Both Ga and In maps reveal an inhomogeneous axial distribution inside single NWs. The analysis of NWs from the same sample but with different dimensions suggests a decrease of In segregation with the reduction of NW diameter, while Ga distribution seems to remain unaltered. Photoluminescence and Raman scattering measurements carried out on ensembles of NWs exhibit relevant signatures of the compositional disorder. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim"],["dc.description.sponsorship","NANOWIRING [265073]"],["dc.identifier.doi","10.1002/pssr.201004527"],["dc.identifier.isi","000288178800003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/23695"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1862-6254"],["dc.title","Direct observation of elemental segregation in InGaN nanowires by X-ray nanoprobe"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","51"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Annalen der Physik"],["dc.bibliographiccitation.lastpage","61"],["dc.bibliographiccitation.volume","523"],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Cros, A."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Gomez-Gomez, M. I."],["dc.contributor.author","Garcia-Cristobal, A."],["dc.contributor.author","de Lima, M. M., Jr."],["dc.contributor.author","Daudin, B."],["dc.contributor.author","Rizzi, Angela"],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.date.accessioned","2018-11-07T09:00:41Z"],["dc.date.available","2018-11-07T09:00:41Z"],["dc.date.issued","2011"],["dc.description.abstract","In this paper we review some recent results on the optical properties of nitride nanostructures, in particular on GaN quantum dots (QDs) and InN nanocolumns (NCs). First, we will give a brief introduction on the particularities of vibrational modes of wurtzite. The GaN QDs, embedded in AlN, were grown by molecular beam epitaxy (MBE) in the Stransky-Krastanov mode on c-and a-plane 6H-SiC. We have studied the optical properties by means of photoluminescence (PL) and performed Raman scattering measurements to analyze the strain relaxation in the dots and the barrier, the effect of the internal electric fields, and the influence of specific growth parameters, like the influence of capping or the spacer on the relaxation of the QDs. A theoretical model, based on continuous elastic theory, were developed to interpret the Raman scattering results. On the other hand, InN NCs have been grown by MBE in the vapor-liquid-solid mode using Au as a catalyst. The nanocolumns have different morphology depending on the growth conditions. The optical properties can be correlated to the morphology of the samples and the best growth conditions can be selected. We observe, from the analysis of the Raman data in InN NCs, the existence of two space regions contributing to the scattering: the surface and the inner region. From the inner region, uncoupled phonon modes are clearly observed, showing the high crystal quality and the complete relaxation of the NCs (no strain). The observation of a LO-phonon-plasmon couple in the same spectra is a fingerprint of the accumulation layer predicted at the surface of the nanocolumns. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim"],["dc.identifier.doi","10.1002/andp.201000107"],["dc.identifier.isi","000285931500003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/24233"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1521-3889"],["dc.relation.issn","0003-3804"],["dc.title","Optical properties of nitride nanostructures"],["dc.type","review"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","864"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","physica status solidi (RRL) - Rapid Research Letters"],["dc.bibliographiccitation.lastpage","867"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Gomez-Gomez, M. I."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Martinez-Criado, G."],["dc.contributor.author","Chu, M. H."],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.contributor.author","Rizzi, Angela"],["dc.date.accessioned","2018-11-07T09:18:55Z"],["dc.date.available","2018-11-07T09:18:55Z"],["dc.date.issued","2013"],["dc.description.abstract","The radial alloy distribution of In-x Ga1-xN nanowires grown by plasma-assisted molecular beam epitaxy has been investigated by three different techniques with nanometric spatial resolution and capability to study single nanowires. Energy-dispersive X-ray spectroscopy radial line-scans revealed a gradient in the alloy composition of individual nanowires. Resonant Raman scattering and spatially resolved X-ray diffraction showed the existence of three distinctive regions with different alloy composition. The combination of the three techniques provides robust evidence of the spontaneous formation of a core-shell structure with a thin Ga-richer shell wrapping an In-rich core at the bottom part of the nanowires. This composition-modulated nanostructure offers an attractive way to explore new device concepts in fully epitaxial nanowire-based solar cells. ((c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)"],["dc.identifier.doi","10.1002/pssr.201307244"],["dc.identifier.isi","000328484500018"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28515"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1862-6270"],["dc.relation.issn","1862-6254"],["dc.title","Radial composition of single InGaN nanowires: a combined study by EDX, Raman spectroscopy, and X-ray diffraction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","125319"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","82"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Molina-Sanchez, A."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Garcia-Cristobal, A."],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Iikawa, F."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.contributor.author","Rizzi, Angela"],["dc.date.accessioned","2018-11-07T08:39:08Z"],["dc.date.available","2018-11-07T08:39:08Z"],["dc.date.issued","2010"],["dc.description.abstract","Photoluminescence excitation (PLE) spectra have been measured for a set of self-assembled InN nanowires (NWs) and a high-crystalline quality InN layer grown by molecular-beam epitaxy. The PLE experimental lineshapes have been reproduced by a self-consistent calculation of the absorption in a cylindrical InN NW. The differences in the PLE spectra can be accounted for the inhomogeneous electron distribution within the NWs caused by a bulk donor concentration (N(D)(+)) and a two-dimensional density of ionized surface states (N(ss)(+)). For NW radii larger than 30 nm, N(D)(+) and N(ss)(+) modify the absorption edge and the lineshape, respectively, and can be determined from the comparison with the experimental data."],["dc.identifier.doi","10.1103/PhysRevB.82.125319"],["dc.identifier.isi","000282008800002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18918"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1098-0121"],["dc.title","Inhomogeneous free-electron distribution in InN nanowires: Photoluminescence excitation experiments"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1300"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Nano Letters"],["dc.bibliographiccitation.lastpage","1305"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Martinez-Criado, G."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.contributor.author","Rizzi, Angela"],["dc.date.accessioned","2018-11-07T09:42:51Z"],["dc.date.available","2018-11-07T09:42:51Z"],["dc.date.issued","2014"],["dc.description.abstract","In this work, we report on the composition, short- and long-range structural order of single molecular beam epitaxy grown InxGa1-xN nanowires using a hard X-ray synchrotron nanoprobe. Nano-X-ray fluorescence mapping reveals an axial and radial heterogeneous elemental distribution in the single wires with Ga accumulation at their bottom and outer regions. Polarization-dependent nano-X-ray absorption near edge structure demonstrates that despite the elemental modulation, the tetrahedral order around the Ga atoms remains along the nanowires. Nano-X-ray diffraction mapping on single nanowires shows the existence of at least three different phases at their bottom: an In-poor shell and two In-rich phases. The alloy homogenizes toward the top of the wires, where a single In-rich phase is observed. No signatures of In-metallic precipitates are observed in the diffraction spectra. The In-content along the single nanowires estimated from X-ray fluorescence and diffraction data are in good agreement. A rough picture of these phenomena is briefly presented. We anticipate that this methodology will contribute to a greater understanding of the underlying growth concepts not only of nanowires but also of many nanostructures in materials science."],["dc.description.sponsorship","NANOWIRING Marie Curie ITN (EU) [PITN-GA-2010-265073]"],["dc.identifier.doi","10.1021/nl4042752"],["dc.identifier.isi","000335720300031"],["dc.identifier.pmid","24502255"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34056"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","1530-6992"],["dc.relation.issn","1530-6984"],["dc.title","Phase Separation in Single InxGa1-xN Nanowires Revealed through a Hard X-ray Synchrotron Nanoprobe"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","115305"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","79"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.contributor.author","Rizzi, Angela"],["dc.date.accessioned","2018-11-07T08:32:26Z"],["dc.date.available","2018-11-07T08:32:26Z"],["dc.date.issued","2009"],["dc.description.abstract","Vertically self-aligned InN nanocolumns have been investigated by means of scanning electron microscopy, Raman scattering, and photoluminescence spectroscopy. Different nanocolumn morphologies corresponding to different molecular beam epitaxy growth conditions have been studied. Raman spectra revealed strain-free nanocolumns with high crystalline quality for the full set of samples studied. Longitudinal optical modes both uncoupled and coupled to an electron plasma coexist in the Raman spectra pointing to the existence of two distinctive regions in the nanocolumn: a surface layer of degenerated electrons and a nondegenerated inner core. The characteristics of the low-temperature photoluminescence and its dependence on temperature and excitation power can be explained by a model considering localized holes recombining with degenerated electrons close to the nonpolar surface. The differences observed in the optical response of different samples showing similar crystalline quality have been attributed to the variation in the electron accumulation layer with the growth conditions."],["dc.identifier.doi","10.1103/PhysRevB.79.115305"],["dc.identifier.isi","000264768900087"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17342"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1550-235X"],["dc.relation.issn","1098-0121"],["dc.title","Optical studies of MBE-grown InN nanocolumns: Evidence of surface electron accumulation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","136511"],["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Journal of Applied Physics"],["dc.bibliographiccitation.volume","113"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Martinez-Criado, G."],["dc.contributor.author","Chu, M. H."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.contributor.author","Rizzi, Angela"],["dc.date.accessioned","2018-11-07T09:26:06Z"],["dc.date.available","2018-11-07T09:26:06Z"],["dc.date.issued","2013"],["dc.description.abstract","This work reports on the elemental distribution and local structure of single InxGa1-xN nanowires (NWs) grown by molecular beam epitaxy on Si (111) substrates using X-ray fluorescence nanoprobe. Ga and In maps reveal an inhomogeneous elemental distribution along the NWs, with a higher Ga concentration at the bottom of the NW. Scanning electron microscopy images show that the inhomogeneous axial distribution is not correlated with a X-ray beam induced damage, and therefore, should be an intrinsic characteristic of the NWs arising from the growth process. Spatially resolved X-ray absorption near edge structure spectroscopy data acquired around the In K-edge show that the tetrahedral structure is preserved around the absorbing In-atoms all along the NW, and suggests that the compositional modulation could be affecting its long-range order. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795544]"],["dc.description.sponsorship","NANOWIRING Marie Curie ITN (EU) [PITN-GA-2010-265073]"],["dc.identifier.doi","10.1063/1.4795544"],["dc.identifier.isi","000317238000078"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30220"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Inst Physics"],["dc.relation.issn","0021-8979"],["dc.title","Synchrotron nanoimaging of single In-rich InGaN nanowires"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Annalen der Physik"],["dc.bibliographiccitation.volume","523"],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Cros, A."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Gomez-Gomez, M. I."],["dc.contributor.author","Garcia-Cristobal, A."],["dc.contributor.author","de Lima, M. M., Jr."],["dc.contributor.author","Daudin, B."],["dc.contributor.author","Rizzi, Angela"],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, Joerg"],["dc.date.accessioned","2018-11-07T08:50:14Z"],["dc.date.available","2018-11-07T08:50:14Z"],["dc.date.issued","2011"],["dc.format.extent","957"],["dc.identifier.doi","10.1002/andp.201100180"],["dc.identifier.isi","000297044800011"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21652"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","0003-3804"],["dc.title","Optical properties of nitride nanostructures (vol 523, pg 51, 2011)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1678"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","physica status solidi (c)"],["dc.bibliographiccitation.lastpage","1681"],["dc.bibliographiccitation.volume","5"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Werner, F."],["dc.contributor.author","Malindretos, J."],["dc.contributor.author","Rizzi, A."],["dc.date.accessioned","2021-12-08T12:30:42Z"],["dc.date.available","2021-12-08T12:30:42Z"],["dc.date.issued","2008"],["dc.identifier.doi","10.1002/pssc.200778585"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/96524"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-476"],["dc.relation.eissn","1610-1642"],["dc.relation.issn","1610-1634"],["dc.rights.uri","http://doi.wiley.com/10.1002/tdm_license_1.1"],["dc.title","Photoluminescence and Raman spectroscopy of MBE-grown InN nanocolumns"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","S553"],["dc.bibliographiccitation.issue","S2"],["dc.bibliographiccitation.journal","physica status solidi (c)"],["dc.bibliographiccitation.lastpage","S556"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Segura-Ruiz, J."],["dc.contributor.author","Garro, N."],["dc.contributor.author","Cantarero, A."],["dc.contributor.author","Iikawa, F."],["dc.contributor.author","Denker, C."],["dc.contributor.author","Malindretos, J."],["dc.contributor.author","Rizzi, A."],["dc.date.accessioned","2021-12-08T12:30:42Z"],["dc.date.available","2021-12-08T12:30:42Z"],["dc.date.issued","2009"],["dc.identifier.doi","10.1002/pssc.200880898"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/96528"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-476"],["dc.relation.issn","1862-6351"],["dc.rights.uri","http://doi.wiley.com/10.1002/tdm_license_1.1"],["dc.title","Optical properties of InN nanocolumns: Electron accumulation at InN non-polar surfaces and dependence on the growth conditions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]