Controllable synthesis of molybdenum tungsten disulfide alloy for vertically composition-controlled multilayer

The effective synthesis of two-dimensional transition metal dichalcogenides alloy is essential for successful application in electronic and optical devices based on a tunable band gap. Here we show a synthesis process for Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> alloy using sulfurization of super-cycle atomic layer deposition Mo<inf>1-x</inf>W<inf>x</inf>O<inf>y</inf>. Various spectroscopic and microscopic results indicate that the synthesized Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> alloys have complete mixing of Mo and Watoms and tunable band gap by systematically controlled composition and layer number. Based on this, we synthesize a vertically composition-controlled (VCC) Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer using five continuous super-cycles with different cycle ratios for each super-cycle. Angle-resolved X-ray photoemission spectroscopy, Raman and ultraviolet-visible spectrophotometer results reveal that a VCC Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer has different vertical composition and broadband light absorption with strong interlayer coupling within a VCC Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer. Further, we demonstrate that a VCC Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer photodetector generates three to four times greater photocurrent than MoS<inf>2</inf>-and WS<inf>2</inf>-based devices, owing to the broadband light absorption. © 2015 Macmillan Publishers Limitedopen1

Ferd Gullivers til Pinkulinganna,

Mode of access: Internet

Contexts that discriminate: international perspectives on the education of Roma students

Theoretical assumptions about educational disadvantages of minority students can be broadly distinguished between approaches assuming that inequality is triggered by characteristics of the minority students (their parents and communities) and approaches assuming that inequality is triggered by characteristics of institutional schooling and its surrounding dominant discourses (Diefenbach 2010 Diefenbach, H. 2010. Kinder und Jugendliche aus Migrantenfamilien im deutschen Bildungssystem: Erklärungen und empirische Befunde [Children and Youth from Migrant Families in the German Education System: Explanations Empirical Results]. 3rd ed. Wiesbaden: VS Verlag. 10.1007/978-3-531-92186-0[CrossRef], 90). Several articles published in this journal have emphasised the latter approach and explored the complex dynamics of racial and ethnic discrimination in education (e.g. Araújo 2016 Araújo, M. 2016. “A Very ‘Prudent Integration’: White Flight, School Segregation and the Depoliticization of (Anti-)Racism.” Race Ethnicity and Education 19 (2): 300–323. doi:10.1080/13613324.2014.969225.[Taylor & Francis Online], [Web of Science ®]; Beratan 2008 Beratan, G. D. 2008. “The Song Remains the Same: Transposition and the Disproportionate Representation of Minority Students in Special Education.” Race Ethnicity and Education 11 (4): 337–354. doi:10.1080/13613320802478820.[Taylor & Francis Online], [Web of Science ®]; Gafford Muhammad 2009 Gafford Muhammad, C. 2009. “Mississippi Higher Education Desegregation and the Interest Convergence Principle: A Crt Analysis of the ‘Ayers Settlement’.” Race Ethnicity and Education 12 (3): 319–336. doi:10.1080/13613320903178279.[Taylor & Francis Online], [Web of Science ®]; Gillies and Robinson 2012 Gillies, V., and Y. Robinson. 2012. “Including While Excluding: Race, Class and Behaviour Support Units.” Race Ethnicity and Education 15 (2): 157–174. doi:10.1080/13613324.2011.578126.[Taylor & Francis Online], [Web of Science ®]; Hamilton, Bloomer, and Potter 2012 Hamilton, J., F. Bloomer, and M.Potter. 2012. “The Adequacy of Traveller Education in Northern Ireland.” Race Ethnicity and Education 15 (4): 501–524. doi:10.1080/13613324.2011.645574.[Taylor & Francis Online], [Web of Science ®]; Johnson 2007 Johnson, E. 2007. “Schooling, Blackness and National Identity in Esmeraldas, Ecuador.” Race Ethnicity and Education 10 (1): 47–70. doi:10.1080/13613320601100377.[Taylor & Francis Online]; Kruss 2001 Kruss, G. 2001. “Towards Human Rights in South African Schools: An agenda for research and practice.” Race Ethnicity and Education 4 (1): 45–62. doi:10.1080/713693047.[Taylor & Francis Online], [CSA]; Webb 2015 Webb, A. 2015. “Indigenous Schooling Grants in Chile: The Impacts of an Integrationist Affirmative Action Policy Among Mapuche Pupils.” Race Ethnicity and Education 18 (3): 419–441. doi:10.1080/13613324.2014.918944.[Taylor & Francis Online], [Web of Science ®]). This special issue follows this tradition by concentrating on the ways in which education systems and prevailing discourses disadvantage minority learners

Hydrophobicity of Rare Earth Oxides Grown by Atomic Layer Deposition

Rare earth oxide (REO) atomic layer deposition (ALD) processes are investigated for hydrophobic coatings. Thermal and plasma-enhanced ALD (PE-ALD) Er2O3 and Dy2O3 are developed using the newly synthesized Er and Dy precursors bis-methylcyclopentadienyl-diisopropyl-acetamidinate-erbium and bis-isopropylcyclopentadienyl-diisopropyl-acetamidinate-dysprosium, with H2O and O-2 plasma counter oxidants. The Er and Dy precursors show typical ALD growth characteristics with no nucleation incubation, indicating that they are suitable ALD precursors. The hydrophobicities of ALD-grown Er2O3 and D2O3 are investigated, together with those of ALD-grown Y(2)O(3)Z, La2O3, and CeO2 that were previously developed for high-k applications. All the ALD-grown REOs show high hydrophobicity, with water contact angles as high as 90 degrees. After annealing at 500 degrees C in air for 2h, hydrophobicity is degraded depending on the kind of material; this degradation is related to the hygroscopy of REOs. In addition, we demonstrate the fabrication of a superhydrophobic surface by depositing highly conformal ALD REO films on 3D Si nanowire nanostructures. The Si NWs are conformally coated with ALD Y2O3, yielding a surface with a water contact angle of about 158 degrees. The ALD REOs reported herein should find widespread applicability in the fabrication of robust hydrophobic coatings.close1

Intensive study sites

Intensive study site