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John P, Gómez Ruiz M, van Deurzen L, Lähnemann J, Trampert A, Geelhaar L, Brandt O, Auzelle T. Growth kinetics and substrate stability during high-temperature molecular beam epitaxy of AlN nanowires. Nanotechnology 2023; 34. [PMID: 37579739 DOI: 10.1088/1361-6528/acefd8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/13/2023] [Indexed: 08/16/2023]
Abstract
We study the molecular beam epitaxy of AlN nanowires between 950 °C and 1215 °C, well above the usual growth temperatures, to identify optimal growth conditions. The nanowires are grown by self-assembly on TiN(111) films sputtered onto Al2O3. Above 1100 °C, the TiN film is seen to undergo grain growth and its surface exhibits {111} facets where AlN nucleation preferentially occurs. Modeling of the nanowire elongation rate measured at different temperatures shows that the Al adatom diffusion length maximizes at 1150 °C, which appears to be the optimum growth temperature. However, analysis of the nanowire luminescence shows a steep increase in the deep-level signal already above 1050 °C, associated with O incorporation from the Al2O3substrate. Comparison with AlN nanowires grown on Si, MgO and SiC substrates suggests that heavy doping of Si and O by interdiffusion from the TiN/substrate interface increases the nanowire internal quantum efficiency, presumably due to the formation of a SiNxor AlOxpassivation shell. The outdiffusion of Si and O would also cause the formation of the inversion domains observed in the nanowires. It follows that for optoelectronic and piezoelectric applications, optimal AlN nanowire ensembles should be prepared at 1150 °C on TiN/SiC substrates and will require anex situsurface passivation.
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Affiliation(s)
- P John
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - M Gómez Ruiz
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L van Deurzen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, United States of America
| | - J Lähnemann
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - A Trampert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - O Brandt
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - T Auzelle
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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Oliva M, Kaganer V, Pudelski M, Meister S, Tahraoui A, Geelhaar L, Brandt O, Auzelle T. A route for the top-down fabrication of ordered ultrathin GaN nanowires. Nanotechnology 2023; 34:205301. [PMID: 36745915 DOI: 10.1088/1361-6528/acb949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
We introduce a facile route for the top-down fabrication of ordered arrays of GaN nanowires with aspect ratios exceeding 10 and diameters below 20 nm. Highly uniform thin GaN nanowires are first obtained by lithographic patterning a bilayer Ni/SiNxhard mask, followed by a combination of dry and wet etching in KOH. The SiNxis found to work as an etch stop during wet etching, which eases reproducibility. Arrays with nanowire diameters down to (33 ± 5) nm can be achieved with a uniformity suitable for photonic applications. Next, a scheme for digital etching is demonstrated to further reduce the nanowire diameter down to 5 nm. However, nanowire breaking or bundling is observed for diameters below ≈20 nm, an effect that is associated to capillary forces acting on the nanowires during sample drying in air. Explicit calculations of the nanowire buckling states under capillary forces indicate that nanowire breaking is favored by the incomplete wetting of water on the substrate surface during drying. The observation of intense nanowire photoluminescence at room-temperature indicates good compatibility of the fabrication route with optoelectronic applications. The process can be principally applied to any GaN/SiNxnanostructures and allows regrowth after removal of the SiNxmask.
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Affiliation(s)
- M Oliva
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - V Kaganer
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - M Pudelski
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - S Meister
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - A Tahraoui
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - O Brandt
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - T Auzelle
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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Sinito C, Corfdir P, Pfüller C, Gao G, Bartolomé J, Kölling S, Doblado AR, Jahn U, Lähnemann J, Auzelle T, Zettler JK, Flissikowski T, Koenraad P, Grahn HT, Geelhaar L, Fernández-Garrido S, Brandt O. Correction to Absence of Quantum-Confined Stark Effect in GaN Quantum Disks Embedded in (Al,Ga)N Nanowires Grown by Molecular Beam Epitaxy. Nano Lett 2020; 20:6930. [PMID: 32794760 DOI: 10.1021/acs.nanolett.0c02938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
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Sinito C, Corfdir P, Pfüller C, Gao G, Bartolomé J, Kölling S, Rodil Doblado A, Jahn U, Lähnemann J, Auzelle T, Zettler JK, Flissikowski T, Koenraad P, Grahn HT, Geelhaar L, Fernández-Garrido S, Brandt O. Absence of Quantum-Confined Stark Effect in GaN Quantum Disks Embedded in (Al,Ga)N Nanowires Grown by Molecular Beam Epitaxy. Nano Lett 2019; 19:5938-5948. [PMID: 31385709 DOI: 10.1021/acs.nanolett.9b01521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Several of the key issues of planar (Al,Ga)N-based deep-ultraviolet light-emitting diodes could potentially be overcome by utilizing nanowire heterostructures, exhibiting high structural perfection, and improved light extraction. Here, we study the spontaneous emission of GaN/(Al,Ga)N nanowire ensembles grown on Si(111) by plasma-assisted molecular beam epitaxy. The nanowires contain single GaN quantum disks embedded in long (Al,Ga)N nanowire segments essential for efficient light extraction. These quantum disks are found to exhibit intense light emission at unexpectedly high energies, namely, significantly above the GaN bandgap, and almost independent of the disk thickness. An in-depth investigation of the actual structure and composition of the nanowires reveals a spontaneously formed Al gradient both along and across the nanowire, resulting in a complex core/shell structure with an Al-deficient core and an Al-rich shell with continuously varying Al content along the entire length of the (Al,Ga)N segment. This compositional change along the nanowire growth axis induces a polarization doping of the shell that results in a degenerate electron gas in the disk, thus screening the built-in electric fields. The high carrier density not only results in the unexpectedly high transition energies but also in radiative lifetimes depending only weakly on temperature, leading to a comparatively high internal quantum efficiency of the GaN quantum disks up to room temperature.
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Affiliation(s)
- C Sinito
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - P Corfdir
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - C Pfüller
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - G Gao
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J Bartolomé
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - S Kölling
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - A Rodil Doblado
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - U Jahn
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J Lähnemann
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - T Auzelle
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J K Zettler
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - T Flissikowski
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - P Koenraad
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - H T Grahn
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - L Geelhaar
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - S Fernández-Garrido
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - O Brandt
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
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Calabrese G, Gao G, van Treeck D, Corfdir P, Sinito C, Auzelle T, Trampert A, Geelhaar L, Brandt O, Fernández-Garrido S. Interfacial reactions during the molecular beam epitaxy of GaN nanowires on Ti/Al 2O 3. Nanotechnology 2019; 30:114001. [PMID: 30681980 DOI: 10.1088/1361-6528/aaf9c5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate the occurrence of interfacial reactions during the self-assembled formation of GaN nanowires on Ti/Al2O3(0001) substrates in plasma-assisted molecular beam epitaxy. The conditions typical for the synthesis of ensembles of long nanowires (>1 μm) are found to promote several chemical reactions. In particular, the high substrate temperature leads to the interdiffusion of Al and O at the Ti/Al2O3 interface resulting in the formation of Al x Ti y O1-x-y and Ti x O1-x compounds. Furthermore, O is found to incorporate into the nanowires degrading their luminescence by heavy n-type doping. At the same time, impinging Ga and N species react with the substrate giving rise to the simultaneous formation of single-crystalline TiN and Ga x Ti y O1-x-y compounds. The latter compounds tend to form hillocks at the substrate surface, on top of which nanowires elongate with large tilt angles with respect to the substrate normal. We develop here a specific process in order to mitigate the detrimental effects of these interfacial reactions, while maintaining the low areal density and absence of coalescence which is the strong asset of growing nanowires on Ti/Al2O3. We find that the combination of a thick Ti film with an intentional low temperature nitridation step preceding nanowire growth and a limited growth temperature results in ensembles of uncoalesced and well-oriented nanowires with luminescence properties comparable to those of standard GaN nanowires prepared on Si. All these properties, together with the inherent benefits of integrating semiconductors on metals, make the present materials combination a promising platform for the further development of group-III nitride nanowire-based devices.
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Affiliation(s)
- G Calabrese
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 57, D-10117 Berlin, Germany
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Zhang X, Lourenço-Martins H, Meuret S, Kociak M, Haas B, Rouvière JL, Jouneau PH, Bougerol C, Auzelle T, Jalabert D, Biquard X, Gayral B, Daudin B. InGaN nanowires with high InN molar fraction: growth, structural and optical properties. Nanotechnology 2016; 27:195704. [PMID: 27041669 DOI: 10.1088/0957-4484/27/19/195704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The structural and optical properties of axial GaN/InGaN/GaN nanowire heterostructures with high InN molar fractions grown by molecular beam epitaxy have been studied at the nanoscale by a combination of electron microscopy, extended x-ray absorption fine structure and nano-cathodoluminescence techniques. InN molar fractions up to 50% have been successfully incorporated without extended defects, as evidence of nanowire potentialities for practical device realisation in such a composition range. Taking advantage of the N-polarity of the self-nucleated GaN NWs grown by molecular beam epitaxy on Si(111), the N-polar InGaN stability temperature diagram has been experimentally determined and found to extend to a higher temperature than its metal-polar counterpart. Furthermore, annealing of GaN-capped InGaN NWs up to 800 °C has been found to result in a 20 times increase of photoluminescence intensity, which is assigned to point defect curing.
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Affiliation(s)
- Xin Zhang
- Univ. Grenoble Alpes, 38000 Grenoble, France. CEA, INAC-PHELIQS, 'Nanophysique et semiconducteurs' group, 38000 Grenoble, France. ALEDIA, 17 rue des martyrs, Bât. M23, 38054 Grenoble Cedex 9, France
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Minj A, Cros A, Garro N, Colchero J, Auzelle T, Daudin B. Assessment of Polarity in GaN Self-Assembled Nanowires by Electrical Force Microscopy. Nano Lett 2015; 15:6770-6. [PMID: 26380860 DOI: 10.1021/acs.nanolett.5b02607] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In this work, we demonstrate the capabilities of atomic force microscopies (AFMs) for the nondestructive determination of the polarity of GaN nanowires (NWs). Three complementary AFMs are analyzed here: Kelvin probe force microscopy (KPFM), light-assisted KPFM, and piezo-force microscopy (PFM). These techniques allow us to assess the polarity of individual NWs over an area of tens of μm(2) and provide statistics on the polarity of the ensemble with an accuracy hardly reachable by other methods. The precise quantitative analysis of the tip-sample interaction by multidimensional spectroscopic measurements, combined with advanced data analysis, has allowed the separate characterization of electrostatic and van der Waals forces as a function of tip-sample distance. Besides their polarity, the net surface charge density of individual NWs was estimated.
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Affiliation(s)
- A Minj
- Materials Science Institute, University of Valencia , P.O. Box 22085, E46071 Valencia, Spain
| | - A Cros
- Materials Science Institute, University of Valencia , P.O. Box 22085, E46071 Valencia, Spain
| | - N Garro
- Materials Science Institute, University of Valencia , P.O. Box 22085, E46071 Valencia, Spain
| | - J Colchero
- Facultad de Química, Departamento de Física, Universidad de Murcia , 30100 Murcia, Spain
| | - T Auzelle
- Université Grenoble Alpes, INAC-SP2M , F-38000 Grenoble, France
- CEA, INAC-SP2M , F-38054 Grenoble, France
| | - B Daudin
- Université Grenoble Alpes, INAC-SP2M , F-38000 Grenoble, France
- CEA, INAC-SP2M , F-38054 Grenoble, France
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Rodrigues J, Ben Sedrine N, Felizardo M, Soares MJ, Alves E, Neves AJ, Fellmann V, Tourbot G, Auzelle T, Daudin B, Boćkowski M, Lorenz K, Monteiro T. GaN:Pr3+ nanostructures for red solid state light emission. RSC Adv 2014. [DOI: 10.1039/c4ra08571j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photoluminescence study of praseodymium implanted and annealed GaN films, quantum wells, nanowires and quantum dots.
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Rodrigues J, Miranda SMC, Fernandes AJS, Nogales E, Alves LC, Alves E, Tourbot G, Auzelle T, Daudin B, Méndez B, Trindade T, Lorenz K, Costa FM, Monteiro T. Towards the understanding of the intentionally induced yellow luminescence in GaN nanowires. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pssc.201200714] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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