Microstructure of epitaxial scandium nitride films grown on silicon

Moram, M. A.; Joyce, Tim; Chalker, Paul R.; Barber, Z. H.; Humphreys, C. J.

doi:10.1016/j.apsusc.2005.11.069

Cited by 32 publications

(26 citation statements)

References 12 publications

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“…The deposition conditions and properties of optimised ScN layers on silicon have previously been described [13] and an optimum deposition temperature of 850 1C was identified. However, for this study, a number of other films grown under non-optimised conditions (at temperatures varying from 650 to 900 1C) were also employed in order to assist in determining the effects of variation in buffer layer properties upon the subsequently grown GaN.…”

Section: Methodsmentioning

confidence: 99%

“…Employing different deposition conditions can give a limited degree of control over film crystallinity. However, for optimum deposition conditions [13], the film crystallinity qualitatively improves upon increasing film thickness, as measured by X-ray diffraction integrated peak intensities (over and above the monotonic rise in intensity intrinsically expected for increasingly thick films). Thicker films would also be expected to act as more effective diffusion barriers.…”

Section: Scn Buffer Layersmentioning

confidence: 98%

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Growth of dislocation-free GaN islands on Si(111) using a scandium nitride buffer layer

Moram

Kappers

Joyce

et al. 2007

Journal of Crystal Growth

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Section: Methodsmentioning

confidence: 99%

Section: Scn Buffer Layersmentioning

confidence: 98%

Growth of dislocation-free GaN islands on Si(111) using a scandium nitride buffer layer

Moram

Kappers

Joyce

et al. 2007

Journal of Crystal Growth

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“…Optical absorption studies were performed on the ScN/c-GaN/ GaAs samples, giving a bandgap for ScN between 2.1 and 2.2 eV, in agreement with the literature [12].…”

Section: Article In Pressmentioning

confidence: 99%

“…Epitaxial growth of ScN has, however, been achieved using a number of techniques on different substrates. Techniques include magnetron sputtering onto MgO(0 0 1) [4,6], rf sputtering and plasma-assisted physical vapour deposition onto quartz, sapphire and Si substrates [7], hydride vapour phase epitaxy onto sapphire [8] and SiC [9] as well as molecular beam epitaxy (MBE) onto MgO [10], sapphire(0 0 0 1) [10,11], Si(111) [12] and Si(0 0 1) [13]. Results indicate that ScN, either takes on the substrate orientation or is polycrystalline.…”

Section: Introductionmentioning

confidence: 99%

Growth of ScN epitaxial films by plasma-assisted molecular beam epitaxy

Hall

Moram

Sanchez

et al. 2009

Journal of Crystal Growth

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“…Morem et al studied MBE deposition of 111 oriented ScN on Si (111). 134 They show that the quality of ScN film depends on the growth temperature. The highest ScN films quality on Si(111) was grown at optimum growth temperature of 850°C.…”

Section: Review Of Scandium Nitride (Scn)mentioning

confidence: 99%

Design of Transition-Metal Nitride Thin Films for Thermoelectrics

Kerdsongpanya

2015

Linköping Studies in Science and Technology. Dissertations

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Thermoelectric devices are one of the promising energy harvesting technologies, because of their ability to convert heat (temperature gradient) to electricity by the Seebeck effect. Furthermore, thermoelectric devices can be used for cooling or heating by the inverse effect (Peltier effect). Since this conversion process is clean, with no emission of greenhouse gases during the process, this technology is attractive for recovering waste heat in automobiles or industries into usable electricity. However, the conversion efficiency of such devices is rather low due to fundamental materials limitations manifested through the thermoelectric figure of merit (ZT ). Thus, there is high demand on finding materials with high ZT or strategies to improve ZT of materials.In this thesis, I discuss the basics of thermoelectrics and how to improve ZT of materials, including present-day strategies. Based on these ideas, I propose a new class of materials for thermoelectric applications: transition-metal nitrides, mainly ScN, CrN and their solid solutions. Here, I employed both experimental and theoretical methods to synthesize and study their thermoelectric properties. My study envisages ways for improving the thermoelectric figure of merit of ScN and possible new materials for thermoelectric applications.The results of my studies show that ScN is a promising thermoelectric material since it exhibits high thermoelectric power factor 2.5×10 −3 Wm −1 K −2 at 800 K, due to low metallic-like electrical resistivity while retained relatively large Seebeck coefficient. My studies on thermal conductivity of ScN also suggest a possibility to control thermal conductivity by tailoring the microstructure of ScN thin films. Furthermore, my theoretical studies on effects of impurities and stoichiometry on the electronic structure of ScN suggest the possibly to improve ScN ZT by stoichiometry tuning and doping. For CrN and Cr1−xScxN solid solution thin films, the results show that the power factor of CrN (8×10 −4Wm −1 K −2 at 770 K) can be retained for the solid solution Cr0.92Sc0.08N. Finally, density functional theory was used to enable a systematic predictionbased strategy for optimizing ScN thermoelectric properties via phase stability of solid solutions. Sc1−xGdxN and Sc1−xLuxN are stabilized as disordered solid solutions, while in the Sc-Nb-N and Sc-Ta-N systems, the inherently layered ternary structures ScNbN2 and ScTaN2 are stable. Svensk sammanfattningSedan den industriella revolutionen har fossila bränslen varit vår huvudkälla till energi i motorer för transport, elproduktion och uppvärmning av byggnader. Eftersom mänskligheten och vår teknik växer för varje år som går, fortsätter efterfrågan på fossila bränslen att öka. Med tanke på att fossila bränslen inte är förnybara, riskerar vi att de tar slut. Dessutom är resultatet av denna ständiga förbränning av fossila bränslen generering av växthusgaser, t.ex. kolmonoxid och koldioxid, som orsakar klimatförändringar, som ett ytterligare problem. Således finns det ett ökande behov...

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Microstructure of epitaxial scandium nitride films grown on silicon

Cited by 32 publications

References 12 publications

Growth of dislocation-free GaN islands on Si(111) using a scandium nitride buffer layer

Growth of dislocation-free GaN islands on Si(111) using a scandium nitride buffer layer

Growth of ScN epitaxial films by plasma-assisted molecular beam epitaxy

Design of Transition-Metal Nitride Thin Films for Thermoelectrics

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