A. Talin - Academia.edu (original) (raw)
Papers by A. Talin
In-situ, Real-Time Monitoring of Mechanical and Chemical Structure Changes in a V2O5 Battery Electrode Using a MEMS Optical Sensor, 2014
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1996
Ballistic electron emission microscopy ͑BEEM͒ is a technique for the measurement of nanoscopic sp... more Ballistic electron emission microscopy ͑BEEM͒ is a technique for the measurement of nanoscopic spatial variations in the barrier height of metal-semiconductor contacts. We have used BEEM in conjunction with simultaneous scanning tunneling microscopy observations of topography, as well as cross-sectional and plan-view transmission electron microscopy, to investigate diode nonidealities and relate them to microstructure. Au/ZnSe and PtSi/Si diodes were examined using these techniques. When analyzed with the parallel conduction model, distributions of barrier heights observed by BEEM in area scans agree well with values measured by conventional techniques and reported in the literature. The wider Au/ZnSe barrier height distribution is thought to be correlated with a rougher interface structure than the PtSi/Si.
Sol-Gel Optics VI, 2002
In this work, we report the effect of annealing temperature on the properties of epitaxial PbZr0.... more In this work, we report the effect of annealing temperature on the properties of epitaxial PbZr0.52Ti0.48O3 (PZT) films deposited using sol-gel techniques on (001) Si substrates with a thin, epitaxial SrTiO3 (STO) interlayer. The STO is grown on silicon using molecular beam epitaxy (MBE) and acts as the template for PZT growth. We report the values for stress, density, thickness,
2006 IEEE International Reliability Physics Symposium Proceedings, 2006
Abstract We characterize the electrical breakdown response for planar structures, fabricated usi... more Abstract We characterize the electrical breakdown response for planar structures, fabricated using microelectromechanical systems (MEMS) methods and materials, to enable design of high voltage microswitches. Electrode configurations that use multiple air gaps provide voltage ...
Fourth International Conference on Thin Film Physics and Applications, 2000
ABSTRACT
This method produces a field emitter material having a uniform electron emitting surface and a lo... more This method produces a field emitter material having a uniform electron emitting surface and a low turn-on voltage. Field emitter materials having uniform electron emitting surfaces as large as 1 square meter and turn-on voltages as low as 16V/μm can be produced from films of electron emitting materials such as polycrystalline diamond, diamond-like carbon, graphite and amorphous carbon by the
Physical Review B, 1994
Nanometer-resolved spatial variations in the Schottky barrier height of a Au/n-type GaAs diode. A... more Nanometer-resolved spatial variations in the Schottky barrier height of a Au/n-type GaAs diode. A. Alec Talin and R. Stanley Williams Department of Chemistry and Biochemistry and Solid State Science Center, University of California ...
We demonstrate that nanoporous metalorganic frameworks (MOFs) loaded with silver can serve as te... more We demonstrate that nanoporous metalorganic frameworks (MOFs) loaded with silver can serve as templates for ordered nanostructures comprising either silver nanoparticles or nanowires. Exposure to an electron beam breaks down the template, leading to rapid silver coalescence ...
Proceedings of SPIE - The International Society for Optical Engineering, 2009
We report the first observation of coherent plasmon emission of THz radiation from arrays of semi... more We report the first observation of coherent plasmon emission of THz radiation from arrays of semiconductor nanowires. The THz signal strength from InAs nanowires is comparable to a planar substrate, indicating the nanowires are highly efficient emitters. This is explained by the preferential orientation of plasma motion to the wire surface, which overcomes radiation trapping by total-internal reflection. Using a bulk Drude model, we identify the average donor density and mobility in the nanowires in a non-contact manner. Contact I-V transconductance measurements provide order of magnitude agreement with values obtained from the THz spectra.
MRS Proceedings, 1996
ABSTRACT
MRS Proceedings, 2002
... D. Jordan, J. Edwards, Jr. and K. Moore Physical Sciences Research Laboratories – Motorola La... more ... D. Jordan, J. Edwards, Jr. and K. Moore Physical Sciences Research Laboratories – Motorola Labs, 7700 S. River Parkway, MD ML26, Tempe, AZ 85284, USA *jimmy.yu@motorola.com ABSTRACT In this paper, we review ...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1995
The effects of K and Li deposition on the emission characteristics of Spindt-type thin-film field... more The effects of K and Li deposition on the emission characteristics of Spindt-type thin-film field emission microcathode arrays [Spindt {ital et} {ital al}. J. Appl. Phys. {bold 47}, 5248 (1976)] (TFFEMC) with Mo tips are discussed. The amount by which each alkali metal lowered the effective work function of a TFFEMC is reported and compared to results of similar measurements performed with a clean Mo(100) surface. In addition, it is shown that the emission current is enhanced during exposure to K flux, even after a saturation coverage has been established. These results are interpreted with a model based on an excess K coverage produced during dosing, which enhances the overall emission of the array.
Journal of Nanophotonics, 2008
ABSTRACT
Nature Materials, 2013
Photoelectrochemical (PEC) water splitting represents a promising route for renewable production ... more Photoelectrochemical (PEC) water splitting represents a promising route for renewable production of hydrogen, but trade-offs between photoelectrode stability and efficiency have greatly limited the performance of PEC devices. In this work, we employ a metal-insulator-semiconductor (MIS) photoelectrode architecture that allows for stable and efficient water splitting using narrow bandgap semiconductors. Substantial improvement in the performance of Si-based MIS photocathodes is demonstrated through a combination of a high-quality thermal SiO2 layer and the use of bilayer metal catalysts. Scanning probe techniques were used to simultaneously map the photovoltaic and catalytic properties of the MIS surface and reveal the spillover-assisted evolution of hydrogen off the SiO2 surface and lateral photovoltage driven minority carrier transport over distances that can exceed 2 cm. The latter finding is explained by the photo- and electrolyte-induced formation of an inversion channel immediately beneath the SiO2/Si interface. These findings have important implications for further development of MIS photoelectrodes and offer the possibility of highly efficient PEC water splitting.
Nano Letters, 2011
We demonstrate an electrochemically driven optical switch based on absorption modulation of surfa... more We demonstrate an electrochemically driven optical switch based on absorption modulation of surface plasmon polaritons (SPPs) propagating in a metallic nanoslit waveguide containing nanocrystals of electrochromic Prussian Blue dye. Optical transmission modulation of ∼96% is achieved by electrochemically switching the dye between its oxidized and reduced states using voltages below 1 V. High spatial overlap and long interaction length between the SPP and the active material are achieved by preferential growth of PB nanocrystals on the nanoslit sidewalls. The resulting orthogonalization between the directions of light propagation and that of charge transport from the electrolyte to ultrathin active material inside the nanoslit waveguide offers significant promise for the realization of electrochromic devices with record switching speeds.
Materials Chemistry and Physics, 1996
Ballistic electron emission microscopy (BEEM) measurements have been made on Au contacts to Si, G... more Ballistic electron emission microscopy (BEEM) measurements have been made on Au contacts to Si, GaAs, InxGa t_xP, and ZnSe. For each semiconductor studied, a distribution of barrier heights (BHs) was observed. The distributions were compared with the current-voltage (I/V) and capacitance-voltage (C/V) characteristics of each metal/semiconductor contact. The BH distributions increase in width with increasing doping and/or complexity of the substrate. The effect of discrete, ionized dopants in the depletion region is considered as one source of BH distribution widening. Average BEEM measurements agree well with the BH computed from I~ V and C/V measurements for all diodes if the effects of thermionic field emission and image force lowering are considered. These results demonstrate the unique application of BEEM for the nanoscale evaluation of semiconductor interface inhomogeneities critical to the control of macroscopic electronic properties.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1996
Electron field emission from two amorphous, tetrahedrally bonded diamondlike carbon films, one wi... more Electron field emission from two amorphous, tetrahedrally bonded diamondlike carbon films, one with (a-tC:N), and a second without nitrogen doping (a-tC͒, prepared by pulsed laser deposition has been investigated using a scanning probe apparatus with micrometer spatial resolution. Electric fields of 100 V/m ͑180 V/m͒ were required to initiate emission from our a-tC:N (a-tC͒ films; however, once emission was established at a particular location, electrons could be drawn at average fields as low as 10 V/m ͑60 V/m͒ from the same region. The initiation of emission was concomitant with electrical discharges which were observed by video techniques. These discharges left craters with micrometer dimensions on the surfaces of otherwise smooth films.
Journal of the American Chemical Society, 2008
In this work we demonstrate the concept of stress-induced chemical detection using metalorganic f... more In this work we demonstrate the concept of stress-induced chemical detection using metalorganic frameworks (MOFs) by integrating a thin film of the MOF HKUST-1 with a microcantilever surface. The results show that the energy of molecular adsorption, which causes slight distortions in the MOF crystal structure, can be efficiently converted to mechanical energy to create a highly responsive, reversible, and selective sensor. This sensor responds to water, methanol, and ethanol vapors, but yields no response to either N 2 or O 2 . The magnitude of the signal, which is measured by a built-in piezoresistor, is correlated with the concentration and can be fitted to a Langmuir isotherm. Furthermore, we show that the hydration state of the MOF layer can be used to impart selectivity to CO 2 . We also report the first use of surface-enhanced Raman spectroscopy to characterize the structure of a MOF film. We conclude that the synthetic versatility of these nanoporous materials holds great promise for creating recognition chemistries to enable selective detection of a wide range of analytes. A force field model is described that successfully predicts changes in MOF properties and the uptake of gases. This model is used to predict adsorption isotherms for a number of representative compounds, including explosives, nerve agents, volatile organic compounds, and polyaromatic hydrocarbons. The results show that, as a result of relatively large heats of adsorption (> 20 kcal mol -1 ) in most cases, we expect an onset of adsorption by MOF as low as 10 -6 kPa, suggesting the potential to detect compounds such as RDX at levels as low as 10 ppb at atmospheric pressure.
In-situ, Real-Time Monitoring of Mechanical and Chemical Structure Changes in a V2O5 Battery Electrode Using a MEMS Optical Sensor, 2014
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1996
Ballistic electron emission microscopy ͑BEEM͒ is a technique for the measurement of nanoscopic sp... more Ballistic electron emission microscopy ͑BEEM͒ is a technique for the measurement of nanoscopic spatial variations in the barrier height of metal-semiconductor contacts. We have used BEEM in conjunction with simultaneous scanning tunneling microscopy observations of topography, as well as cross-sectional and plan-view transmission electron microscopy, to investigate diode nonidealities and relate them to microstructure. Au/ZnSe and PtSi/Si diodes were examined using these techniques. When analyzed with the parallel conduction model, distributions of barrier heights observed by BEEM in area scans agree well with values measured by conventional techniques and reported in the literature. The wider Au/ZnSe barrier height distribution is thought to be correlated with a rougher interface structure than the PtSi/Si.
Sol-Gel Optics VI, 2002
In this work, we report the effect of annealing temperature on the properties of epitaxial PbZr0.... more In this work, we report the effect of annealing temperature on the properties of epitaxial PbZr0.52Ti0.48O3 (PZT) films deposited using sol-gel techniques on (001) Si substrates with a thin, epitaxial SrTiO3 (STO) interlayer. The STO is grown on silicon using molecular beam epitaxy (MBE) and acts as the template for PZT growth. We report the values for stress, density, thickness,
2006 IEEE International Reliability Physics Symposium Proceedings, 2006
Abstract We characterize the electrical breakdown response for planar structures, fabricated usi... more Abstract We characterize the electrical breakdown response for planar structures, fabricated using microelectromechanical systems (MEMS) methods and materials, to enable design of high voltage microswitches. Electrode configurations that use multiple air gaps provide voltage ...
Fourth International Conference on Thin Film Physics and Applications, 2000
ABSTRACT
This method produces a field emitter material having a uniform electron emitting surface and a lo... more This method produces a field emitter material having a uniform electron emitting surface and a low turn-on voltage. Field emitter materials having uniform electron emitting surfaces as large as 1 square meter and turn-on voltages as low as 16V/μm can be produced from films of electron emitting materials such as polycrystalline diamond, diamond-like carbon, graphite and amorphous carbon by the
Physical Review B, 1994
Nanometer-resolved spatial variations in the Schottky barrier height of a Au/n-type GaAs diode. A... more Nanometer-resolved spatial variations in the Schottky barrier height of a Au/n-type GaAs diode. A. Alec Talin and R. Stanley Williams Department of Chemistry and Biochemistry and Solid State Science Center, University of California ...
We demonstrate that nanoporous metalorganic frameworks (MOFs) loaded with silver can serve as te... more We demonstrate that nanoporous metalorganic frameworks (MOFs) loaded with silver can serve as templates for ordered nanostructures comprising either silver nanoparticles or nanowires. Exposure to an electron beam breaks down the template, leading to rapid silver coalescence ...
Proceedings of SPIE - The International Society for Optical Engineering, 2009
We report the first observation of coherent plasmon emission of THz radiation from arrays of semi... more We report the first observation of coherent plasmon emission of THz radiation from arrays of semiconductor nanowires. The THz signal strength from InAs nanowires is comparable to a planar substrate, indicating the nanowires are highly efficient emitters. This is explained by the preferential orientation of plasma motion to the wire surface, which overcomes radiation trapping by total-internal reflection. Using a bulk Drude model, we identify the average donor density and mobility in the nanowires in a non-contact manner. Contact I-V transconductance measurements provide order of magnitude agreement with values obtained from the THz spectra.
MRS Proceedings, 1996
ABSTRACT
MRS Proceedings, 2002
... D. Jordan, J. Edwards, Jr. and K. Moore Physical Sciences Research Laboratories – Motorola La... more ... D. Jordan, J. Edwards, Jr. and K. Moore Physical Sciences Research Laboratories – Motorola Labs, 7700 S. River Parkway, MD ML26, Tempe, AZ 85284, USA *jimmy.yu@motorola.com ABSTRACT In this paper, we review ...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1995
The effects of K and Li deposition on the emission characteristics of Spindt-type thin-film field... more The effects of K and Li deposition on the emission characteristics of Spindt-type thin-film field emission microcathode arrays [Spindt {ital et} {ital al}. J. Appl. Phys. {bold 47}, 5248 (1976)] (TFFEMC) with Mo tips are discussed. The amount by which each alkali metal lowered the effective work function of a TFFEMC is reported and compared to results of similar measurements performed with a clean Mo(100) surface. In addition, it is shown that the emission current is enhanced during exposure to K flux, even after a saturation coverage has been established. These results are interpreted with a model based on an excess K coverage produced during dosing, which enhances the overall emission of the array.
Journal of Nanophotonics, 2008
ABSTRACT
Nature Materials, 2013
Photoelectrochemical (PEC) water splitting represents a promising route for renewable production ... more Photoelectrochemical (PEC) water splitting represents a promising route for renewable production of hydrogen, but trade-offs between photoelectrode stability and efficiency have greatly limited the performance of PEC devices. In this work, we employ a metal-insulator-semiconductor (MIS) photoelectrode architecture that allows for stable and efficient water splitting using narrow bandgap semiconductors. Substantial improvement in the performance of Si-based MIS photocathodes is demonstrated through a combination of a high-quality thermal SiO2 layer and the use of bilayer metal catalysts. Scanning probe techniques were used to simultaneously map the photovoltaic and catalytic properties of the MIS surface and reveal the spillover-assisted evolution of hydrogen off the SiO2 surface and lateral photovoltage driven minority carrier transport over distances that can exceed 2 cm. The latter finding is explained by the photo- and electrolyte-induced formation of an inversion channel immediately beneath the SiO2/Si interface. These findings have important implications for further development of MIS photoelectrodes and offer the possibility of highly efficient PEC water splitting.
Nano Letters, 2011
We demonstrate an electrochemically driven optical switch based on absorption modulation of surfa... more We demonstrate an electrochemically driven optical switch based on absorption modulation of surface plasmon polaritons (SPPs) propagating in a metallic nanoslit waveguide containing nanocrystals of electrochromic Prussian Blue dye. Optical transmission modulation of ∼96% is achieved by electrochemically switching the dye between its oxidized and reduced states using voltages below 1 V. High spatial overlap and long interaction length between the SPP and the active material are achieved by preferential growth of PB nanocrystals on the nanoslit sidewalls. The resulting orthogonalization between the directions of light propagation and that of charge transport from the electrolyte to ultrathin active material inside the nanoslit waveguide offers significant promise for the realization of electrochromic devices with record switching speeds.
Materials Chemistry and Physics, 1996
Ballistic electron emission microscopy (BEEM) measurements have been made on Au contacts to Si, G... more Ballistic electron emission microscopy (BEEM) measurements have been made on Au contacts to Si, GaAs, InxGa t_xP, and ZnSe. For each semiconductor studied, a distribution of barrier heights (BHs) was observed. The distributions were compared with the current-voltage (I/V) and capacitance-voltage (C/V) characteristics of each metal/semiconductor contact. The BH distributions increase in width with increasing doping and/or complexity of the substrate. The effect of discrete, ionized dopants in the depletion region is considered as one source of BH distribution widening. Average BEEM measurements agree well with the BH computed from I~ V and C/V measurements for all diodes if the effects of thermionic field emission and image force lowering are considered. These results demonstrate the unique application of BEEM for the nanoscale evaluation of semiconductor interface inhomogeneities critical to the control of macroscopic electronic properties.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1996
Electron field emission from two amorphous, tetrahedrally bonded diamondlike carbon films, one wi... more Electron field emission from two amorphous, tetrahedrally bonded diamondlike carbon films, one with (a-tC:N), and a second without nitrogen doping (a-tC͒, prepared by pulsed laser deposition has been investigated using a scanning probe apparatus with micrometer spatial resolution. Electric fields of 100 V/m ͑180 V/m͒ were required to initiate emission from our a-tC:N (a-tC͒ films; however, once emission was established at a particular location, electrons could be drawn at average fields as low as 10 V/m ͑60 V/m͒ from the same region. The initiation of emission was concomitant with electrical discharges which were observed by video techniques. These discharges left craters with micrometer dimensions on the surfaces of otherwise smooth films.
Journal of the American Chemical Society, 2008
In this work we demonstrate the concept of stress-induced chemical detection using metalorganic f... more In this work we demonstrate the concept of stress-induced chemical detection using metalorganic frameworks (MOFs) by integrating a thin film of the MOF HKUST-1 with a microcantilever surface. The results show that the energy of molecular adsorption, which causes slight distortions in the MOF crystal structure, can be efficiently converted to mechanical energy to create a highly responsive, reversible, and selective sensor. This sensor responds to water, methanol, and ethanol vapors, but yields no response to either N 2 or O 2 . The magnitude of the signal, which is measured by a built-in piezoresistor, is correlated with the concentration and can be fitted to a Langmuir isotherm. Furthermore, we show that the hydration state of the MOF layer can be used to impart selectivity to CO 2 . We also report the first use of surface-enhanced Raman spectroscopy to characterize the structure of a MOF film. We conclude that the synthetic versatility of these nanoporous materials holds great promise for creating recognition chemistries to enable selective detection of a wide range of analytes. A force field model is described that successfully predicts changes in MOF properties and the uptake of gases. This model is used to predict adsorption isotherms for a number of representative compounds, including explosives, nerve agents, volatile organic compounds, and polyaromatic hydrocarbons. The results show that, as a result of relatively large heats of adsorption (> 20 kcal mol -1 ) in most cases, we expect an onset of adsorption by MOF as low as 10 -6 kPa, suggesting the potential to detect compounds such as RDX at levels as low as 10 ppb at atmospheric pressure.