Silanna Semiconductor

Sydney Olympic, Australia

Silanna Semiconductor

Sydney Olympic, Australia

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Flynn C.,Silanna Semiconductor | Sim L.W.,Silanna Semiconductor
Thin Solid Films | Year: 2015

Aluminium nitride (AlN) films grown by molecular beam epitaxy (MBE) were exposed to phosphoric acid (H3PO4) heated to 70 °C for 10 min. The H3PO4 treatment removed excess aluminium (Al) from the surface of AlN grown under Al-rich conditions. A side effect of the H3PO4 process was the formation of hexagonal etch pits up to 180 nm in size. Reflectance measurements were performed before and after the removal of excess Al from the film surface. Excess surface Al in the form of droplets was found to strongly influence the reflectance of the AlN films. Consequently the Al surface droplets (AlSD) introduced an error into film thickness values derived from Lorentz oscillator model fitting of the specular reflectance. The film thickness measurement error due to excess surface Al was quantified as a function of the AlSD surface coverage percentage. The effect of AlSD on reflectance-based film thickness measurements must be taken into account when using AlN grown in the Al droplet regime to characterize the nitrogen (N) growth rate. © 2015 Elsevier B.V.


Hudson D.D.,University of Sydney | Singh N.,University of Sydney | Yu Y.,Australian National University | Grillet C.,École Centrale Lyon | And 7 more authors.
2015 IEEE Summer Topicals Meeting Series, SUM 2015 | Year: 2015

We demonstrate an octave spanning, 1.9-6.2 μm supercontinuum generation in a low loss silicon on a sapphire (SOS) nanowire. The supercontinuum is achieved by pumping in the low-loss window of SOS near 3.7 μm. © 2015 IEEE.


Flynn C.,Silanna Semiconductor | Stewart M.,Silanna Semiconductor | Stewart M.,Elcometer
Materials Research Express | Year: 2016

Aluminium nitride (AlN) films were grown on c-plane sapphire wafers by molecular beam epitaxy (MBE) under aluminium-rich conditions. The excess aluminium (Al) accumulated on the surface of the films as micro-scale droplets 1-10 μmin size, and as Al nanoparticles with diameters in the range 10-110 nm. Photoluminescence (PL) measurements were performed on the AlN samples using a 193 nmExcimer laser as the excitation source. Prior to PL measurements the wafers were cleaved in half. One half of each wafer was submitted to a 10 min treatment in H3PO4 heated to 70 °C to remove the excess Al from the film surface. The remaining half was left in the as-deposited condition. The mean intensities of the near-band-edge PL peaks of the as-deposited samples were 2.0-3.4 times higher compared to the samples subjected to the H3PO4 Al-removal treatment. This observation motivated calculations to determine the optimal Al surface nanosphere size for plasmonic enhancement of PL from AlN. The PL enhancement was found to peak for an Al nanosphere radius of 15 nm, which is within the range of the experimentally-observed Al nanoparticle sizes. © 2016 IOP Publishing Ltd.


Li F.,Institute of Photonics and Optical Science IPOS | Jackson S.D.,Institute of Photonics and Optical Science IPOS | Grillet C.,Institute of Photonics and Optical Science IPOS | Magi E.,Institute of Photonics and Optical Science IPOS | And 9 more authors.
Optics Express | Year: 2011

We report record low loss silicon-on-sapphire nanowires for applications to mid infrared optics. We achieve propagation losses as low as 0.8dB/cm at λ = 1550nm, ∼1.1 to 1.4dB/cm at λ = 2080nm and < 2dB/cm at λ = 5.18 μm. © 2011 Optical Society of America.


Silvestri L.,University of New South Wales | Dunn K.,Silanna Semiconductor | Prawer S.,University of Melbourne | Ladouceur F.,University of New South Wales
Applied Physics Letters | Year: 2011

The properties of Si and O donors in wurtzite AlN have been studied by means of hybrid functional calculations, finding that both impurities form DX centres. In the case of Si, the stable DX centre is close in energy to the substitutional donor state and to a second metastable DX centre, thus explaining both the persistent effects and the broad range of activation energies observed experimentally. Ionisation energies have been computed for both Si and O donor states. © 2011 American Institute of Physics.


Singh N.,University of Sydney | Hudson D.D.,University of Sydney | Yu Y.,Australian National University | Grillet C.,École Centrale Lyon | And 7 more authors.
Conference on Lasers and Electro-Optics Europe - Technical Digest | Year: 2015

We demonstrate an octave spanning, 1.9-6.2 μm supercontinuum generation in a low loss silicon on a sapphire (SOS) nanowire. This establishes SOS as a promising new platform for integrated nonlinear photonics in the mid-IR. © 2015 OSA.


Flynn C.,Silanna Semiconductor | Lee W.,Silanna Semiconductor
Materials Research Express | Year: 2014

Magnesium-doped GaN (GaN:Mg) films having Mg concentrations in the range 5×1018-5×1020 cm-3 were fabricated by molecular beam epitaxy. Raman spectroscopy was employed to study the effects of Mg incorporation on the positions of the E2 and A1(LO) lines identifiable in the Raman spectra. For Mg concentrations in excess of 2 × 1019 cm-3, increases in the Mg concentration shift both lines to higher wave numbers. The shifts of the Raman lines reveal a trend towards compressive stress induced by incorporation of Mg into the GaN films. The observed correlation between the Mg concentration and the Raman line positions establish Raman spectroscopy as a useful tool for optimizing growth of Mg-doped GaN. © 2014 IOP Publishing Ltd.


Flynn C.,Silanna Semiconductor | Atanackovic P.,Silanna Semiconductor | Enjeti L.,Silanna Semiconductor
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2012

Strain and defects produced by implantation of Si + ions into r-plane sapphire are studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Post-implantation annealing carried out at temperatures up to 1100°C is observed to reduce strain and the number of defects. The peak value of strain falls linearly with increasing annealing temperature. Peaks in the strain depth profiles correspond to the regions of highest defect density. Roughness and amorphous content at the surface can be reduced by high temperature annealing. © 2012 Elsevier B.V. All rights reserved.


Silvestri L.,University of New South Wales | Dunn K.,Silanna Semiconductor | Prawer S.,University of Melbourne | Ladouceur F.,University of New South Wales
EPL | Year: 2012

Formation energies and concentrations of the most relevant point defects in n-type wurtzite AlN are obtained by first-principle calculations employing a hybrid functional. We show that the incorporation of Si is favoured over O under N-rich growth conditions, but not under Al-rich conditions. The triply negatively charged Al vacancy is found to be the defect with the lowest formation energy in n-type AlN and it is therefore expected to be the main compensating acceptor. Under typical physical vapor-phase transport growth conditions, we predict Si concentrations of up to 10 20 cm - 3 and net donor concentrations of about 10 18 cm - 3, in good agreement with available experimental data. Copyright © 2012 EPLA.


Singh N.,University of Sydney | Hudson D.D.,University of Sydney | Yu Y.,Australian National University | Grillet C.,École Centrale Lyon | And 7 more authors.
CLEO: Science and Innovations, CLEO-SI 2015 | Year: 2015

We demonstrate an octave spanning, 1.9-6.2 μm supercontinuum generation in a low loss silicon on a sapphire (SOS) nanowire. This establishes SOS as a promising new platform for integrated nonlinear photonics in the mid-IR. © OSA 2015.

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