liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
Alternative names
Publications (10 of 35) Show all publications
Bairagi, S., Chang, J.-C., Tarntair, F.-G., Wu, W.-Y., Gueorguiev, G. K., de Almeida, E. F., . . . Hsiao, C.-L. (2023). Formation of quaternary Zn(AlxGa1−x)2O4 epilayers driven by thermally induced interdiffusion between spinel ZnGa2O4 epilayer and Al2O3 substrate. Materials Today Advances, 20, Article ID 100422.
Open this publication in new window or tab >>Formation of quaternary Zn(AlxGa1−x)2O4 epilayers driven by thermally induced interdiffusion between spinel ZnGa2O4 epilayer and Al2O3 substrate
Show others...
2023 (English)In: Materials Today Advances, ISSN 2590-0498, Vol. 20, article id 100422Article in journal (Refereed) Published
Abstract [en]

Zinc aluminogallate, Zn(AlxGa1−x)2O4 (ZAGO), a single-phase spinel structure, offers considerable potential for high-performance electronic devices due to its expansive compositional miscibility range between aluminum (Al) and gallium (Ga). Direct growth of high-quality ZAGO epilayers however remains problematic due to the high volatility of zinc (Zn). This work highlights a novel synthesis process for high-quality epitaxial quaternary ZAGO thin films on sapphire substrates, achieved through thermal annealing of a ZnGa2O4 (ZGO) epilayer on sapphire in an ambient air setting. In-situ annealing x-ray diffraction measurements show that the incorporation of Al in the ZGO epilayer commenced at 850 °C. The Al content (x) in ZAGO epilayer gradually increased up to around 0.45 as the annealing temperature was raised to 1100 °C, which was confirmed by transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy. X-ray rocking curve measurement revealed a small full width at half maximum value of 0.72 °, indicating the crystal quality preservation of the ZAGO epilayer with a high Al content. However, an epitaxial intermediate �–(AlxGa1−x)2O3 layer (� - AGO) was formed between the ZAGO and sapphire substrate. This is believed to be a consequence of the interdiffusion of Al and Ga between the ZGO thin film and sapphire substrate. Using density functional theory, the substitution cost of Ga in sapphire was determined to be about 0.5 eV lower than substitution cost of Al in ZGO. Motivated by this energetically favorable substitution, a formation mechanism of the ZAGO and AGO layers was proposed. Spectroscopic ellipsometry studies revealed an increase in total thickness of the film from 105.07 nm (ZGO) to 147.97 nm (ZAGO/AGO) after annealing to 1100 °C, which were corroborated using TEM. Furthermore, an observed increase in the direct (indirect) optical bandgap from 5.06 eV (4.7 eV) to 5.72 eV (5.45 eV) with an increasing Al content in the ZAGO layer further underpins the formation of a quaternary ZAGO alloy with a tunable composition.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Zinc aluminogallate; Ellipsometry; Semiconductors; Annealing; Interdiffusion; Bandgap
National Category
Condensed Matter Physics Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-197989 (URN)10.1016/j.mtadv.2023.100422 (DOI)001081449100001 ()
Note

Funding agencies;This research was funded by Vetenskapsrådet (2018–04198), Energimyndigheten (46658-1), and Stiftelsen Olle Engkvist Byggmästare (197–0210), STINT (MG2019-8485), and Stiftelsen för Strategisk Forskning (2009-00971). The Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU 2009-00971) is acknowledged for financial support. We acknowledge the support from Wafer Works Corporation, National Science and Technology Council (Taiwan) (112-2218-E-A49-024-MBK, 112-2622-8-A49-013-SB, MOST 111-2923-E-A49 -003 -MY3), and MAtek (2021-T-006).

Available from: 2023-09-20 Created: 2023-09-20 Last updated: 2023-11-03
Chang, J.-C., Tseng, E. N., Lo, Y.-L., Nayak, S. K., Lundin, D., Persson, P. O. Å., . . . Hsiao, C.-L. (2023). HiPIMS-grown AlN buffer for threading dislocation reduction in DC-magnetron sputtered GaN epifilm on sapphire substrate. Vacuum, 217, Article ID 112553.
Open this publication in new window or tab >>HiPIMS-grown AlN buffer for threading dislocation reduction in DC-magnetron sputtered GaN epifilm on sapphire substrate
Show others...
2023 (English)In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 217, article id 112553Article in journal (Refereed) Published
Abstract [en]

Gallium nitride (GaN) epitaxial films on sapphire (Al2O3) substrates have been grown using reactive magnetron sputter epitaxy with a liquid Ga target. Threading dislocations density (TDD) of sputtered GaN films was reduced by using an inserted high-quality aluminum nitride (AlN) buffer layer grown by reactive high power impulse magnetron sputtering (R-HiPIMS) in a gas mixture of Ar and N2. After optimizing the Ar/N2 pressure ratio and deposition power, a high-quality AlN film exhibiting a narrow full-width at half-maximum (FWHM) value of the double-crystal x-ray rocking curve (DCXRC) of the AlN(0002) peak of 0.086° was obtained by R-HiPIMS. The mechanism giving rise the observed quality improvement is attributed to the enhancement of kinetic energy of the adatoms in the deposition process when operated in a transition mode. With the inserted HiPIMS-AlN as a buffer layer for direct current magnetron sputtering (DCMS) GaN growth, the FWHM values of GaN(0002) and (10 1‾ 1) XRC decrease from 0.321° to 0.087° and from 0.596° to 0.562°, compared to the direct growth of GaN on sapphire, respectively. An order of magnitude reduction from 2.7 × 109 cm−2 to 2.0 × 108 cm−2 of screw-type TDD calculated from the FWHM of the XRC data using the inserted HiPIMS-AlN buffer layer demonstrates the improvement of crystal quality of GaN. The result of TDD reduction using the HiPIMS-AlN buffer was also verified by weak beam dark-field (WBDF) cross-sectional transmission electron microscopy (TEM).

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2023
Keywords
GaN; Magnetron sputtering; HiPIMS; Dislocations; XRCTEM
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-197990 (URN)10.1016/j.vacuum.2023.112553 (DOI)001072124300001 ()
Funder
Swedish Research CouncilSwedish Energy AgencyThe Swedish Foundation for International Cooperation in Research and Higher Education (STINT)Carl Tryggers foundation Olle Engkvists stiftelse
Note

Funding agencies: This research was funded by Vetenskapsrådet (grant number 2018-04198), Energimyndigheten (grant number 46658-1), Carl Tryggers Stiftelse (grant number CTS 22:2029) and Stiftelsen Olle Engkvist Byggmästare (grant number 197-0210). The Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU 2009-00971) is acknowledged for financial support. We acknowledge STINT foundation, Sweden, for supporting this international collaboration (grant number: MG2019-8485).

Available from: 2023-09-20 Created: 2023-09-20 Last updated: 2023-12-21
Alves Machado Filho, M., Hsiao, C.-L., dos Santos, R. B., Hultman, L., Birch, J. & Gueorguiev, G. K. (2023). Self-Induced Core–Shell InAlN Nanorods: Formation and Stability Unraveled by Ab Initio Simulations. ACS Nanoscience Au, 3(1), 84-93
Open this publication in new window or tab >>Self-Induced Core–Shell InAlN Nanorods: Formation and Stability Unraveled by Ab Initio Simulations
Show others...
2023 (English)In: ACS Nanoscience Au, E-ISSN 2694-2496, Vol. 3, no 1, p. 84-93Article in journal (Refereed) Published
Abstract [en]

By addressing precursor prevalence and energetics using the DFT-based synthetic growth concept (SGC), the formation mechanism of self-induced InAlN core–shell nanorods (NRs) synthesized by reactive magnetron sputter epitaxy (MSE) is explored. The characteristics of In- and Al-containing precursor species are evaluated considering the thermal conditions at a typical NR growth temperature of around 700 °C. The cohesive and dissociation energies of In-containing precursors are consistently lower than those of their Al-containing counterparts, indicating that In-containing precursors are more weakly bonded and more prone to dissociation. Therefore, In-containing species are expected to exhibit lower abundance in the NR growth environment. At increased growth temperatures, the depletion of In-based precursors is even more pronounced. A distinctive imbalance in the incorporation of Al- and In-containing precursor species (namely, AlN/AlN+, AlN2/AlN2+, Al2N2/Al2N2+, and Al2/Al2+ vs InN/InN+, InN2/InN2+, In2N2/In2N2+, and In2/In2+) is found at the growing edge of the NR side surfaces, which correlates well with the experimentally obtained core–shell structure as well as with the distinctive In-rich core and vice versa for the Al-rich shell. The performed modeling indicates that the formation of the core–shell structure is substantially driven by the precursors’ abundance and their preferential bonding onto the growing edge of the nanoclusters/islands initiated by phase separation from the beginning of the NR growth. The cohesive energies and the band gaps of the NRs show decreasing trends with an increment in the In concentration of the NRs’ core and with an increment in the overall thickness (diameter) of the NRs. These results reveal the energy and electronic reasons behind the limited growth (up to ∼25% of In atoms of all metal atoms, i.e., InxAl1–xN, x ∼ 0.25) in the NR core and may be qualitatively perceived as a limiting factor for the thickness of the grown NRs (typically <50 nm).

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
Keywords
self-induced InAlN core−shell nanorods; synthetic growth concept; DFT; reactive magnetron sputter epitaxy; precursor species; nucleation and structural evolution of nanostructures; immiscible systems at nanoscale
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-197988 (URN)10.1021/acsnanoscienceau.2c00041 (DOI)001091274000001 ()37101465 (PubMedID)
Funder
Swedish Research Council, 2018-04198Swedish Research Council, 2018-05973Swedish Research Council, SNIC 2022/23-137Swedish Research Council, SNIC 2022/5-135Swedish Energy Agency, 46658-1Linköpings universitet, 2009-00971
Note

Funding: Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials (AFM) at Linkoping University [2009-00971]; Swedish Research Council (Vetenskapsradet) [2018-04198]; Swedish Energy Agency (Energimyndigheten) [46658-1]; Brazilian Research agency CNPq; Brazilian Research agency CAPES; Swedish Research Council [2018-05973]

Available from: 2023-09-20 Created: 2023-09-20 Last updated: 2023-11-15Bibliographically approved
Chang, J.-C., Birch, J., Kostov Gueorguiev, G., Bakhit, B., Greczynski, G., Eriksson, F., . . . Hsiao, C.-L. (2022). Domain epitaxial growth of Ta3N5 film on c-plane sapphire substrate. Surface & Coatings Technology, 443, Article ID 128581.
Open this publication in new window or tab >>Domain epitaxial growth of Ta3N5 film on c-plane sapphire substrate
Show others...
2022 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 443, article id 128581Article in journal (Refereed) Published
Abstract [en]

Tritantalum pentanitride (Ta3N5) semiconductor is a promising material for photoelectrolysis of water with high efficiency. Ta3N5 is a metastable phase in the complex system of TaN binary compounds. Growing stabilized single-crystal Ta3N5 films is correspondingly challenging. Here, we demonstrate the growth of a nearly single-crystal Ta3N5 film with epitaxial domains on c-plane sapphire substrate, Al2O3(0001), by magnetron sputter epitaxy. Introduction of a small amount ~2% of O2 into the reactive sputtering gas mixed with N2 and Ar facilitates the formation of a Ta3N5 phase in the film dominated by metallic TaN. In addition, we indicate that a single-phase polycrystalline Ta3N5 film can be obtained with the assistance of a Ta2O5 seed layer. With controlling thickness of the seed layer smaller than 10 nm and annealing at 1000 °C, a crystalline β phase Ta2O5 was formed, which promotes the domain epitaxial growth of Ta3N5 films on Al2O3(0001). The mechanism behind the stabilization of the orthorhombic Ta3N5 structure resides in its stacking with the ultrathin seed layer of orthorhombic β-Ta2O5, which is energetically beneficial and reduces the lattice mismatch with the substrate.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Ta3N5, Sputtering, MSE, XRD, XPS, Water splitting, Single crystal
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-188556 (URN)10.1016/j.surfcoat.2022.128581 (DOI)000868328000003 ()
Note

Funding: Swedish Research Council [2018-04198, 2021-00357]; Swedish Energy Agency [46658-1]; Stiftelsen Olle Engkvist Byggmastare [197-0210]; Linkoping University Library; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]

Available from: 2022-09-16 Created: 2022-09-16 Last updated: 2023-12-21Bibliographically approved
Chang, J.-C., Eriksson, F., Sortica, M. A., Greczynski, G., Bakhit, B., Hu, Z.-J., . . . Hsiao, C.-L. (2021). Orthorhombic Ta3-xN5-yOy thin films grown by unbalanced magnetron sputtering: The role of oxygen on structure, composition, and optical properties. Surface & Coatings Technology, 406, Article ID 126665.
Open this publication in new window or tab >>Orthorhombic Ta3-xN5-yOy thin films grown by unbalanced magnetron sputtering: The role of oxygen on structure, composition, and optical properties
Show others...
2021 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 406, article id 126665Article in journal (Refereed) Published
Abstract [en]

Direct growth of orthorhombic Ta3N5-type Ta-O-N compound thin films, specifically Ta3-xN5-yOy, on Si and sapphire substrates with various atomic fractions is realized by unbalanced magnetron sputtering. Low-degree fiber-textural Ta3-xN5-yOy films were grown through reactive sputtering of Ta in a gas mixture of N-2, Ar, and O-2 with keeping a partial pressure ratio of 3:2:0.1 in a total working pressure range of 5-30 mTorr. With increasing total pressure from 5 to 30 mTorr, the atomic fraction of O in the as-grown Ta3-xN5-yOy films was found to increase from 0.02 to 0.15 while that of N and Ta decrease from 0.66 to 0.54 and 0.33 to 0.31, respectively, leading to a decrease in b lattice constant up to around 1.3%. Metallic TaNx phases were formed without oxygen. For a working pressure of 40 mTorr, an amorphous, O-rich Ta-N-O compound film with a high O fraction of similar to 0.48, was formed, mixed with non-stoichiometric TaON and Ta2O5. By analyzing the plasma discharge, the increasing O incorporation is associated with oxide formation on top of the Ta target due to a higher reactivity of Ta with O than with N. The increase of O incorporation in the films also leads to a optical bandgap widening from similar to 2.22 to similar to 2.96 eV, which is in agreement with the compositional and structural changes from a crystalline Ta3-xN5-yOy to an amorphous O-rich Ta-O-N compound.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2021
Keywords
Ta3N5; Magnetron sputtering; XRD; XPS; ERDA; Optical absorption spectroscopy
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-173006 (URN)10.1016/j.surfcoat.2020.126665 (DOI)000604750600025 ()
Note

Funding Agencies|Vetenskapseddet [2018-04198]; Energimyndigheten [46658-1]; Stiftelsen 011e Engkvist Byggmastare [197-0210]; Linkoping University Library; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; VR-RFI [821-2012-5144, 2017-00646_9]; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research [RIF14-0053, 5E13-0333]

Available from: 2021-01-27 Created: 2021-01-27 Last updated: 2023-12-21
Landälv, L., Rogström, L., Lu, J., Ostach, D., Eriksson, F., Junaid, M., . . . Eklund, P. (2019). Phase evolution of radio frequency magnetron sputtered Cr-rich (Cr,Zr)(2)O-3 coatings studied by in situ synchrotron X-ray diffraction during annealing in air or vacuum. Journal of Materials Research, 34(22), 3735-3746
Open this publication in new window or tab >>Phase evolution of radio frequency magnetron sputtered Cr-rich (Cr,Zr)(2)O-3 coatings studied by in situ synchrotron X-ray diffraction during annealing in air or vacuum
Show others...
2019 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 34, no 22, p. 3735-3746Article in journal (Refereed) Published
Abstract [en]

The phase evolution of reactive radio frequency (RF) magnetron sputtered Cr0.28Zr0.10O0.61 coatings has been studied by in situ synchrotron X-ray diffraction during annealing under air atmosphere and vacuum. The annealing in vacuum shows t-ZrO2 formation starting at similar to 750-800 degrees C, followed by decomposition of the alpha-Cr2O3 structure in conjunction with bcc-Cr formation, starting at similar to 950 degrees C. The resulting coating after annealing to 1140 degrees C is a mixture of t-ZrO2, m-ZrO2, and bcc-Cr. The air-annealed sample shows t-ZrO2 formation starting at similar to 750 degrees C. The resulting coating after annealing to 975 degrees C is a mixture of t-ZrO2 and alpha-Cr2O3 (with dissolved Zr). The microstructure coarsened slightly during annealing, but the mechanical properties are maintained, with no detectable bcc-Cr formation. A larger t-ZrO2 fraction compared with alpha-Cr2O3 is observed in the vacuum-annealed coating compared with the air-annealed coating at 975 degrees C. The results indicate that the studied pseudo-binary oxide is more stable in air atmosphere than in vacuum.

Place, publisher, year, edition, pages
CAMBRIDGE UNIV PRESS, 2019
Keywords
physical vapor deposition (PVD); annealing; oxide
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-163680 (URN)10.1557/jmr.2019.340 (DOI)000510319300001 ()
Note

Funding Agencies|Swedish Research Council (VR)Swedish Research Council [621-20124368, 330-2014-6336]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Marie Sklodowska Curie Actions, Cofund, Project INCA [600398]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 6 program; Swedish Research Council via the Rontgen Angstrom Cluster (RAC) Frame Program [2011-6505]; German Federal Ministry of Education and Research (BMBF)Federal Ministry of Education & Research (BMBF) [05K12CG1]

Available from: 2020-02-17 Created: 2020-02-17 Last updated: 2022-12-19Bibliographically approved
Li, Z., Sun, H., Hsiao, C.-L., Yao, Y., Xiao, Y., Shahi, M., . . . Zhang, F. (2018). A Free-Standing High-Output Power Density Thermoelectric Device Based on Structure-Ordered PEDOT:PSS. Advanced Electronic Materials, 4(2), Article ID 1700496.
Open this publication in new window or tab >>A Free-Standing High-Output Power Density Thermoelectric Device Based on Structure-Ordered PEDOT:PSS
Show others...
2018 (English)In: Advanced Electronic Materials, E-ISSN 2199-160X, Vol. 4, no 2, article id 1700496Article in journal (Refereed) Published
Abstract [en]

A free-standing high-output power density polymeric thermoelectric (TE) device is realized based on a highly conductive (approximate to 2500 S cm(-1)) structure-ordered poly(3,4-ethylenedioxythiophene):polystyrene sulfonate film (denoted as FS-PEDOT:PSS) with a Seebeck coefficient of 20.6 mu V K-1, an in-plane thermal conductivity of 0.64 W m(-1) K-1, and a peak power factor of 107 mu W K-2 m(-1) at room temperature. Under a small temperature gradient of 29 K, the TE device demonstrates a maximum output power density of 99 +/- 18.7 mu W cm(-2), which is the highest value achieved in pristine PEDOT:PSS based TE devices. In addition, a fivefold output power is demonstrated by series connecting five devices into a flexible thermoelectric module. The simplicity of assembling the films into flexible thermoelectric modules, the low out-of-plane thermal conductivity of 0.27 W m(-1) K-1, and free-standing feature indicates the potential to integrate the FS-PEDOT:PSS TE modules with textiles to power wearable electronics by harvesting human bodys heat. In addition to the high power factor, the high thermal stability of the FS-PEDOT:PSS films up to 250 degrees C is confirmed by in situ temperature-dependent X-ray diffraction and grazing incident wide angle X-ray scattering, which makes the FS-PEDOT:PSS films promising candidates for thermoelectric applications.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
free-standing PEDOT:PSS film; output power density; p-type; thermoelectric generators
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:liu:diva-145465 (URN)10.1002/aelm.201700496 (DOI)000424888600015 ()2-s2.0-85039784826 (Scopus ID)
Note

Funding Agencies|Vinnova Marie Curie incoming project [2016-04112]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [200900971]; Recruitment Program of Global Youth Experts; National Natural Science Foundation of China [21474035]; United States National Science Foundation [DMR-1262261]; Open Fund of the State Key Laboratory of Luminescent Materials and Devices [2016-skllmd-03]; European Research Council [ERC 307596]

Available from: 2018-03-13 Created: 2018-03-13 Last updated: 2023-12-06Bibliographically approved
Junaid, M., Hsiao, C.-L., Chen, Y.-T., Lu, J., Palisaitis, J., Persson, P. O., . . . Birch, J. (2018). Effects of N2 Partial Pressure on Growth, Structure, and Optical Properties of GaN Nanorods Deposited by Liquid-Target Reactive Magnetron Sputter Epitaxy. Nanomaterials, 8(4), Article ID 223.
Open this publication in new window or tab >>Effects of N2 Partial Pressure on Growth, Structure, and Optical Properties of GaN Nanorods Deposited by Liquid-Target Reactive Magnetron Sputter Epitaxy
Show others...
2018 (English)In: Nanomaterials, E-ISSN 2079-4991, Vol. 8, no 4, article id 223Article in journal (Refereed) Published
Abstract [en]

GaN nanorods, essentially free from crystal defects and exhibiting very sharp band-edge luminescence, have been grown by reactive direct-current magnetron sputter epitaxy onto Si (111) substrates at a low working pressure of 5 mTorr. Upon diluting the reactive N2 working gas with a small amount of Ar (0.5 mTorr), we observed an increase in the nanorod aspect ratio from 8 to ~35, a decrease in the average diameter from 74 to 35 nm, and a two-fold increase in nanorod density. With further dilution (Ar = 2.5 mTorr), the aspect ratio decreased to 14, while the diameter increased to 60 nm and the nanorod density increased to a maximum of 2.4 × 109 cm−2. Yet, lower N2 partial pressures eventually led to the growth of continuous GaN films. The observed morphological dependence on N2 partial pressure is explained by a change from N-rich to Ga-rich growth conditions, combined with reduced GaN-poisoning of the Ga-target as the N2 gas pressure is reduced. Nanorods grown at 2.5 mTorr N2 partial pressure exhibited a high intensity 4 K photoluminescence neutral donor bound exciton transitions (D0XA) peak at ~3.479 eV with a full-width-at-half-maximum of 1.7 meV. High-resolution transmission electron microscopy corroborated the excellent crystalline quality of the nanorods.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2018
Keywords
GaN, nanorods, X-ray diffraction, TEM, photoluminescence, magnetron sputter epitaxy, sputtering
National Category
Condensed Matter Physics Nano Technology
Identifiers
urn:nbn:se:liu:diva-84654 (URN)10.3390/nano8040223 (DOI)000434889100044 ()
Note

Funding agencies: Swedish Research Council (VR) [621-2013-5360, 621-2012-4420, 2016-04412]; Swedish Government Strategic Research Area Grant in Materials Science AFM-SFO MatLiU [2009-00971]; Knut and Alice Wallenberg Foundation

Available from: 2018-04-09 Created: 2012-10-16 Last updated: 2021-12-29Bibliographically approved
Serban, E. A., Palisaitis, J., Persson, P. O., Hultman, L., Birch, J. & Hsiao, C.-L. (2018). Site-controlled growth of GaN nanorod arrays by magnetron sputter epitaxy. Thin Solid Films, 660, 950-955
Open this publication in new window or tab >>Site-controlled growth of GaN nanorod arrays by magnetron sputter epitaxy
Show others...
2018 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 660, p. 950-955Article in journal (Refereed) Published
Abstract [en]

Catalyst-free GaN nanorod regular arrays have been realized by reactive magnetron sputter epitaxy. Two nanolithographic methods, nanosphere lithography (NSL) and focused ion beam lithography (FIBL), were applied to pattern Si substrates with TiNx masks. The growth temperature was optimized for achieving selectivity and well-faceted nanorods grown onto the NSL-patterned substrates. With increasing temperature from 875 to 985 °C, we observe different growth behaviors and associate them with selective insensitive, diffusion-dominated, and desorption-dominated zones. To further achieve site-specific and diameter control, these growth parameters were transferred onto FIBL-patterned substrates. Further investigation into the FIBL process through tailoring of milling current and time in combination with varying nanorod growth temperature, suggests that minimization of mask and substrate damage is the key to attain uniform, well-defined, single, and straight nanorods. Destruction of the mask results in selective area growth failure, while damage of the substrate surface promotes inclined nanorods grown into the openings, owning to random oriented nucleation.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Gallium nitride, Magnetron sputter epitaxy, Selective-area growth, Nanorods, Lithography, Focused ion beam, Nanosphere
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-147648 (URN)10.1016/j.tsf.2018.01.050 (DOI)000441177500138 ()2-s2.0-85041572645 (Scopus ID)
Note

Funding agencies: Swedish Research Council (VR) [621-2012-4420, 621-2013-5360, 2016-04412]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program; Swedish Foundation for Strategic Research (SSF) [RIF 14-0074]; Sw

Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2021-12-29Bibliographically approved
Serban, A., Palisaitis, J., Junaid, M., Tengdelius, L., Högberg, H., Hultman, L., . . . Hsiao, C.-L. (2017). Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates. Energies, 10(9), Article ID 1322.
Open this publication in new window or tab >>Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates
Show others...
2017 (English)In: Energies, E-ISSN 1996-1073, Vol. 10, no 9, article id 1322Article in journal (Refereed) Published
Abstract [en]

We demonstrate the versatility of magnetron sputter epitaxy by achieving high-quality GaN nanorods on different substrate/template combinations, specifically Si, SiC, TiN/Si, ZrB2/Si, ZrB2/SiC, Mo, and Ti. Growth temperature was optimized on Si, TiN/Si, and ZrB2/Si, resulting in increased nanorod aspect ratio with temperature. All nanorods exhibit high purity and quality, proved by the strong bandedge emission recorded with cathodoluminescence spectroscopy at room temperature as well as transmission electron microscopy. These substrates/templates are affordable compared to many conventional substrates, and the direct deposition onto them eliminates cumbersome post-processing steps in device fabrication. Thus, magnetron sputter epitaxy offers an attractive alternative for simple and affordable fabrication in optoelectronic device technology.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI AG, 2017
Keywords
GaN, nanorods, Si, SiC, Ti, Mo, TiN and ZrB2 templates, magnetron sputtering, epitaxy
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-141597 (URN)10.3390/en10091322 (DOI)000411225200078 ()2-s2.0-85029362447 (Scopus ID)
Note

Funding agencies: Swedish Research Council (VR) [621-2012-4420, 621-2013-5360, 2016-04412]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program; Swedish Foundation for Strategic Research (SSF) through the Resea

Available from: 2017-10-02 Created: 2017-10-02 Last updated: 2023-08-28Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7192-0670

Search in DiVA

Show all publications