Heteroepitaxial ZnO nano hexagons on p-type SiC

Khranovskyy, Volodymyr; Tsiaoussis, I.; Yazdi, Gholamreza; Hultman, Lars; Yakimova, Rositsa

doi:10.1016/j.jcrysgro.2009.09.057

Cited by 28 publications

(25 citation statements)

References 34 publications

(15 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We believe that the fact that SiC substrate is 4° off-cuted favours the nucleation of ZnO nanocrystalls and their epitaxial growth. Earlier we reported in details the growth of ZnO HEX on SiC substrates, assisted by high quality hetero interface and advanced optical properties [24]. We suppose, that the observed features provide the necessary premise for the epitaxial growth of high quality ZnO nanostructures on SiC for unique applications.…”

Section: Zno Nanostructures Grown At Low Precursor Pressurementioning

confidence: 69%

“…It was concluded that the plasma discharge promotes the precursors decomposition and increases the ZnO adatoms mobility, resulting in high quality film formation [23] at lowered temperatures. Recently the integration of the ZnO nanostructures with Si and SiC via APMOCVD has been reported to result in advanced structural and optical properties [24,9]. Here, we applied varying precursor pressure for growth of ZnO nanostructures.…”

Section: Precursors Chemistrymentioning

confidence: 99%

See 1 more Smart Citation

Morphology engineering of ZnO nanostructures

Khranovskyy

Yakimova

2012

Physica B: Condensed Matter

Self Cite

View full text Add to dashboard Cite

The nanosized ZnO structures were grown by atmospheric pressure metalorganic chemical vapor deposition (APMOCVD) at the temperature range 200 -500 °C at variable precursor pressure. The temperature induced evolution of the ZnO microstructure was observed, resulting in regular transformation of the material from conventional polycrystalline layers to hierarchically arranged sheaves of ZnO nanowires. The structures obtained were uniformly planarly located over the substrate and possessed as low nanowires diameter as 30 -45 nm at the tips. The observed growth evolution is explained in term of ZnO crystal planes free energy difference and growth kinetic. For comparison, the convenient growth at constant precursor pressure on Si and SiC substrates has been performed, resulted in island-type grown ZnO nanostructures. The demonstrated nanosized ZnO structures may have unique possible areas of application, which are listed here. PACS keywordsZnO nanostructures, APMOCVD, temperature evolution IntroductionEngineering of the crystal's morphology and microstructure has initiated great research interest. Particularly control of the shapes, size and morphology of novel or mature functional materials is of high interest, enabling manifestation of their novel properties or tailorable functions. Zinc oxide is a promising II-VI semiconductor, having wide band gap ~3.37 eV and a large exciton binding energy ~60 meV at room temperature. It has attracted increasing interest due to its potential applications in electronics [1], photonics [2], sensors [3], transistors [4], field emission displays [5], etc. It is one of the most gifted materials for the fabrication of short-wavelength optoelectronic devices including blue-UV light-emitting and room temperature UV lasing diodes [6]. ZnO possesses one of the richest family of nanostructures: various nanorods, nanopillars, nanowires, nanodonats, nanodrums, nanopropellers, nanonails, nanobridges etc. have been widely reported in literature [7]. However, such exotic morphologies of ZnO nanostructures complicate their functionality, i. e. hamper their practical applications, while the controllable growth of ordered and uniform ZnO nanostructure is highly desirable and may enable their possible applications in various devices. Particular interest represents the hierarchical ZnO nanostructures, being able to combine the high surface-to-volume ratio and fundamental material properties of ZnO, which may be essential for specific applications such as gas-and bio-sensors, hybrid solar cells, etc [8]. Recently, we have demonstrated the ability to grow well-ordered ZnO nanopillars on a seeding layer via selective homoepitaxial growth by atmospheric pressure metalorganic chemical vapor deposition (APMOCVD) [9]. Moreover, by this technique we succeeded in obtaining ZnO nanostructures of diverse morphology. Clear evolution of the

show abstract

Section: Zno Nanostructures Grown At Low Precursor Pressurementioning

confidence: 69%

Section: Precursors Chemistrymentioning

confidence: 99%

Morphology engineering of ZnO nanostructures

Khranovskyy

Yakimova

2012

Physica B: Condensed Matter

Self Cite

View full text Add to dashboard Cite

show abstract

“…10,12 Zn acetylacetonates [Zn(AA) 2 ] and oxygen were used as precursors. Argon gas flow transported the vapor of the thermally decomposed Zn precursor to the reaction zone where due to mixing with oxygen, the ZnO deposits onto the substrate.…”

Section: Methodsmentioning

confidence: 99%

“…The high quality of these nocrystallites explains the intense light emission in the ultraviolet spectral region. 10 The present investigation is important due to the anomalies reported on the epitaxial growth of ZnO on 6H-SiC. 11 The ZnO nanopillars were also deposited on SiO 2 /Si wafers, and the difference in the mode of growth of these nanocrystallites in comparison to the ZnO grown on SiC is discussed.…”

mentioning

confidence: 98%

Structural characterization of ZnO nanopillars grown by atmospheric-pressure metalorganic chemical vapor deposition on vicinal 4H-SiC and SiO2/Si substrates

Tsiaoussis

Khranovskyy

Dimitrakopulos

et al. 2011

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

The structural characteristics of ZnO nanocrystals epitaxially grown on p-type (0001) 4H-SiC substrates were studied by transmission electron microscopy (TEM). The nanocrystallites were grown by atmospheric-pressure metalorganic chemical vapor deposition. The ZnO nanocrystals were formed at terraces introduced by vicinal 4H-SiC substrates toward the [11 20] direction. They had the shape of hexagonal nanopillars, with their edges parallel to the h11 20i directions and a top c-plane facet, reflecting the crystal symmetry of ZnO. The free surface between the hexagonal nanopillars was covered by a very thin and highly defected epitaxial ZnO film, which strongly suggests the Stranski-Krastanov mode of growth. The ZnO/SiC interface was systematically studied by plane view TEM and cross sectional high resolution TEM. The residual strain in the thin continuous film as well as in the nanopillars was estimated from Moiré patterns and by geometrical phase analysis. ZnO was also deposited on the SiO 2 /Si substrate for comparison. The films were polycrystalline exhibiting strong preferred orientation, with the c-axes of the grains almost perpendicular to the substrate resulting in the formation of nanopillars. The differences of nanopillar formation in the two substrates, 4H-SiC and SiO 2 is also discussed.

show abstract

“…Earlier, we demonstrated the change of the texture of the ZnO films from (0001) to (10-11) via Ga doping and the morphology control via respective annealing (144,145). We have recently reported on the control of ZnO nanostructure location and inclination via respective substrate miss cut in the epitaxial growth of ZnO on 4H-SiC (13). Such an approach can be utilized for fabrication of the active ZnO elements for biosensors, being able for operation in liquid.…”

Section: Recent Achievements In Zno Nanocrystal Based Biosensorsmentioning

confidence: 99%