Dr. Vinod Eric Sandana Profile

Dr. Vinod Eric Sandana

SPIE Involvement:

Conference Program Committee | Author

Publications (22)

PROCEEDINGS ARTICLE | March 27, 2018

Sensing based on surface-enhanced Raman scattering using self-forming ZnO nanoarrays coated with gold as substrates

Proc. SPIE. 10533, Oxide-based Materials and Devices IX

KEYWORDS: Gold, Thin films, Glasses, Molecules, Silicon, Surface enhanced Raman spectroscopy, Raman spectroscopy, Raman scattering, Zinc oxide, Thin film coatings

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PROCEEDINGS ARTICLE | March 22, 2018

The new oxide paradigm for solid state ultraviolet photodetectors

Proc. SPIE. 10533, Oxide-based Materials and Devices IX

KEYWORDS: Oxides, Photodetectors, Magnesium, Ultraviolet radiation, Transmittance, Aluminum, Palladium, Silicon carbide, Zinc oxide, Gallium

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The bandgap of wurzite ZnO layers grown on 2 inch diameter c-Al₂O₃ substrates by pulsed laser deposition was engineered from 3.7 to 4.8 eV by alloying with Mg. Above this Mg content the layers transformed from single phase hcp to mixed hcp/fcc phase before becoming single phase fcc above a bandgap of about 5.5 eV. Metal-Semiconductor-Metal (MSM) photodetectors based on gold Inter-Digitated-Transducer structures were fabricated from the single phase hcp layers by single step negative photolithography and then packaged in TO5 cans. The devices gave over 6 orders of magnitude of separation between dark and light signal with solar rejection ratios (I₂₇₀ : I₃₅₀) of over 3 × 10⁵ and dark signals of 300 pA (at a bias of -5V). Spectral responsivities were engineered to fit the “Deutscher Verein des Gas- und Wasserfaches” industry standard form and gave over two decade higher responsivities (14 A/W, peaked at 270 nm) than commercial SiC based devices. Homogeneous Ga₂O₃ layers were also grown on 2 inch diameter c-Al₂O₃ substrates by PLD. Optical transmission spectra were coherent with a bandgap that increased from 4.9 to 5.4 eV when film thickness was decreased from 825 to 145 nm. X-ray diffraction revealed that the films were of the β-Ga₂O₃ (monoclinic) polytype with strong (-201) orientation. β-Ga₂O₃ MSM photodetectors gave over 4 orders of magnitude of separation between dark and light signal (at -5V bias) with dark currents of 250 pA and spectral responsivities of up to 40 A/W (at -0.75V bias). It was found that the spectral responsivity peak position could be decreased from 250 to 230 nm by reducing film thickness from 825 to 145 nm. This shift in peak responsivity wavelength with film thickness (a) was coherent with the apparent bandgap shift that was observed in transmission spectroscopy for the same layers and (b) conveniently provides a coverage of the spectral region in which MgZnO layers show fcc/hcp phase mixing.

PROCEEDINGS ARTICLE | March 6, 2018

Wide and ultra-wide bandgap oxides: where paradigm-shift photovoltaics meets transparent power electronics

Proc. SPIE. 10533, Oxide-based Materials and Devices IX

KEYWORDS: Semiconductors, Oxides, Photovoltaics, Electronics, Solar cells, Silicon, Gallium nitride, Transistors, Silicon carbide, Gallium

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PROCEEDINGS ARTICLE | April 3, 2017

Lithium-doped nickel oxide for p-type dye-sensitized solar cell applications

Proc. SPIE. 10105, Oxide-based Materials and Devices VIII

KEYWORDS: Gold, Oxides, Nanostructuring, Glasses, Nickel, Silicon, Scanning electron microscopy, Sapphire, Dye sensitized solar cells, Wet etching, Zinc oxide

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PROCEEDINGS ARTICLE | March 23, 2017

Investigations on the substrate dependence of the properties in nominally-undoped beta-Ga2O3 thin films grown by PLD

Proc. SPIE. 10105, Oxide-based Materials and Devices VIII

KEYWORDS: Thin films, Crystals, Silicon, Ocean optics, Sapphire, Transmittance, Aluminum, Chlorine, Gallium, Thin film growth

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PROCEEDINGS ARTICLE | March 7, 2017

Identification of acoustic waves in ZnO materials by Brillouin light scattering for SAW device applications

Proc. SPIE. 10105, Oxide-based Materials and Devices VIII

KEYWORDS: Thin films, Scattering, Crystals, Silicon, Light scattering, Wave propagation, Solids, Phonons, Zinc oxide, Acoustics

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PROCEEDINGS ARTICLE | March 24, 2015

Structural, optical, electrical and morphological study of transparent p-NiO/n-ZnO heterojunctions grown by PLD

Proc. SPIE. 9364, Oxide-based Materials and Devices VI

KEYWORDS: Electronics, Transparency, Glasses, Crystals, Scanning electron microscopy, Raman spectroscopy, Transmittance, Transparent conductors, Zinc oxide, Heterojunctions

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PROCEEDINGS ARTICLE | March 24, 2015

Scale-up of the chemical lift-off of (In)GaN-based p-i-n junctions from sapphire substrates using sacrificial ZnO template layers

Proc. SPIE. 9364, Oxide-based Materials and Devices VI

KEYWORDS: Glasses, Ultraviolet radiation, Crystals, Indium, Scanning electron microscopy, Gallium nitride, Sapphire, Indium gallium nitride, Zinc oxide, Industrial chemicals

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PROCEEDINGS ARTICLE | April 2, 2014

Novel method for reclaim/reuse of bulk GaN substrates using sacrificial ZnO release layers

Proc. SPIE. 8987, Oxide-based Materials and Devices V

KEYWORDS: Thin films, Light emitting diodes, Crystals, Atomic force microscopy, Scanning electron microscopy, Gallium nitride, Sapphire, Wet etching, Zinc oxide, Thin film growth

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PROCEEDINGS ARTICLE | March 8, 2014

Nickel oxide growth on Si (111), c-Al2O3 and FTO/glass by pulsed laser deposition

Proc. SPIE. 8987, Oxide-based Materials and Devices V

KEYWORDS: Oxides, Glasses, Annealing, Crystals, Nickel, Silicon, Scanning electron microscopy, Dye sensitized solar cells, Transparent conductors, Pulsed laser deposition

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PROCEEDINGS ARTICLE | March 18, 2013

Comparison of chemical and laser lift-off for the transfer of InGaN-based p-i-n junctions from sapphire to glass substrates

Proc. SPIE. 8626, Oxide-based Materials and Devices IV

KEYWORDS: Glasses, Crystals, Indium, Gallium nitride, Sapphire, Indium gallium nitride, Zinc oxide, Soda-lime glass, Wafer bonding, Laser liftoff

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PROCEEDINGS ARTICLE | March 18, 2013

Graphene versus oxides for transparent electrode applications

Proc. SPIE. 8626, Oxide-based Materials and Devices IV

KEYWORDS: Oxides, Graphene, Electrodes, Solar cells, Copper, Indium, Resistance, Chemical vapor deposition, Transparent conductors, Tin

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PROCEEDINGS ARTICLE | March 18, 2013

Engineering future light emitting diodes and photovoltaics with inexpensive materials: Integrating ZnO and Si into GaN-based devices

Proc. SPIE. 8626, Oxide-based Materials and Devices IV

KEYWORDS: Photovoltaics, Light emitting diodes, Crystals, Indium, Silicon, Gallium nitride, Sapphire, Indium gallium nitride, Zinc oxide, Metalorganic chemical vapor deposition

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Indium Gallium Nitride (InGaN) based PV have the best fit to the solar spectrum of any alloy system and emerging LED lighting based on InGaN technology and has the potential to reduce energy consumption by nearly one half while enabling significant carbon emission reduction. However, getting the maximum benefit from GaN diode -based PV and LEDs will require wide-scale adoption. A key bottleneck for this is the device cost, which is currently dominated by the substrate (i.e. sapphire) and the epitaxy (i.e. GaN). This work investigates two schemes for reducing such costs. First, we investigated the integration of Zinc Oxide (ZnO) in InGaN-based diodes. (Successful growth of GaN on ZnO template layers (on sapphire) was illustrated. These templates can then be used as sacrificial release layers for chemical lift-off. Such an approach provides an alternative to laser lift-off for the transfer of GaN to substrates with a superior cost-performance profile, plus an added advantage of reclaiming the expensive single-crystal sapphire. It was also illustrated that substitution of low temperature n-type ZnO for n-GaN layers can combat indium leakage from InGaN quantum well active layers in inverted p-n junction structures. The ZnO overlayers can also double as transparent contacts with a nanostructured surface which enhances light in/out coupling. Thus ZnO was confirmed to be an effective GaN substitute which offers added flexibility in device design and can be used in order to simultaneously reduce the epitaxial cost and boost the device performance. Second, we investigated the use of GaN templates on patterned Silicon (100) substrates for reduced substrate cost LED applications. Controlled local metal organic chemical vapor deposition epitaxy of cubic phase GaN with on-axis Si(100) substrates was illustrated. Scanning electron microscopy and transmission electron microscopy techniques were used to investigate uniformity and examine the defect structure in the GaN. Our results suggest that groove structures are very promising for controlled local epitaxy of cubic phase GaN. Overall, it is concluded that there are significant opportunities for cost reduction in novel hybrid diodes based on ZnO-InGaN-Si hybridization.

PROCEEDINGS ARTICLE | March 2, 2012

Novel process for direct bonding of GaN onto glass substrates using sacrificial ZnO template layers to chemically lift-off GaN from c-sapphire

Proc. SPIE. 8263, Oxide-based Materials and Devices III

KEYWORDS: Glasses, Crystals, X-ray diffraction, Optical microscopy, Scanning electron microscopy, Gallium nitride, Wet etching, Zinc oxide, Wafer bonding, Single crystal X-ray diffraction

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PROCEEDINGS ARTICLE | March 1, 2012

ZnO nanorod electrodes for hydrogen evolution and storage

Proc. SPIE. 8263, Oxide-based Materials and Devices III

KEYWORDS: Electrodes, Metals, Ions, Silicon, Hydrogen, Platinum, Zinc oxide, Pulsed laser deposition, Thermodynamics, Nanorods

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PROCEEDINGS ARTICLE | March 1, 2012

Energy harvesting from millimetric ZnO single wire piezo-generators

Proc. SPIE. 8263, Oxide-based Materials and Devices III

KEYWORDS: Crystals, Copper, Indium, Silver, Photography, Oxygen, Scanning electron microscopy, Energy harvesting, Zinc oxide, Nanowires

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PROCEEDINGS ARTICLE | March 11, 2011

Amorphous ZnO films grown by room temperature pulsed laser deposition on paper and mylar for transparent electronics applications

Proc. SPIE. 7940, Oxide-based Materials and Devices II

KEYWORDS: Oxides, Electronics, Optical properties, Crystals, Zinc, Adaptive optics, Scanning electron microscopy, Zinc oxide, Pulsed laser deposition, Amorphous semiconductors

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PROCEEDINGS ARTICLE | March 11, 2010

ZnO thin films and nanostructures for emerging optoelectronic applications

Proc. SPIE. 7605, Optoelectronic Integrated Circuits XII

KEYWORDS: Thin films, Nanostructures, Light emitting diodes, Solar cells, Electroluminescence, Gallium nitride, Optoelectronics, Excitons, Indium gallium nitride, Zinc oxide

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PROCEEDINGS ARTICLE | March 2, 2010

Thin film transistors with wurtzite ZnO channels grown on Si3N4/SiO2/Si (111) substrates by pulsed laser deposition

Proc. SPIE. 7603, Oxide-based Materials and Devices

KEYWORDS: Thin films, Visible radiation, Glasses, Silicon, Scanning electron microscopy, Transmittance, Transistors, Field effect transistors, Zinc oxide, Pulsed laser deposition

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PROCEEDINGS ARTICLE | February 24, 2010

Epitaxial MOVPE growth of highly c-axis oriented InGaN/GaN films on ZnO-buffered Si (111) substrates

Proc. SPIE. 7603, Oxide-based Materials and Devices

KEYWORDS: Crystals, Interfaces, Ions, Silicon, Nitrogen, Zinc, Scanning electron microscopy, Gallium nitride, Indium gallium nitride, Zinc oxide

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PROCEEDINGS ARTICLE | February 28, 2009

Fabrication of nanostructured heterojunction LEDs using self-forming moth eye type arrays of n-ZnO nanocones grown on p-si (111) substrates by pulsed laser deposition

Proc. SPIE. 7217, Zinc Oxide Materials and Devices IV

KEYWORDS: Nanostructures, Antireflective coatings, Light emitting diodes, Nanostructuring, Crystals, Silicon, Electroluminescence, Zinc oxide, Heterojunctions, Nanolithography

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PROCEEDINGS ARTICLE | March 7, 2008

MOCVD growth of ZnO nanostructures using Au droplets as catalysts

Proc. SPIE. 6895, Zinc Oxide Materials and Devices III

KEYWORDS: Gold, Nanostructures, Annealing, Silicon, Zinc, Scanning electron microscopy, Zinc oxide, Metalorganic chemical vapor deposition, Nanodroplets, Nanorods

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