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Towards single-chip radiofrequency signal processing via acoustoelectric electron–phonon interactions

Nature Communications

Hackett, Lisa; Miller, Michael R.; Brimigion, Felicia M.; Dominguez, Daniel D.; Peake, Gregory M.; Tauke-Pedretti, Anna; Arterburn, Shawn C.; Friedmann, Thomas A.; Eichenfield, Matthew S.

The addition of active, nonlinear, and nonreciprocal functionalities to passive piezoelectric acoustic wave technologies could enable all-acoustic and therefore ultra-compact radiofrequency signal processors. Toward this goal, we present a heterogeneously integrated acoustoelectric material platform consisting of a 50 nm indium gallium arsenide epitaxial semiconductor film in direct contact with a 41° YX lithium niobate piezoelectric substrate. We then demonstrate three of the main components of an all-acoustic radiofrequency signal processor: passive delay line filters, amplifiers, and circulators. Heterogeneous integration allows for simultaneous, independent optimization of the piezoelectric-acoustic and electronic properties, leading to the highest performing surface acoustic wave amplifiers ever developed in terms of gain per unit length and DC power dissipation, as well as the first-ever demonstrated acoustoelectric circulator with an isolation of 46 dB with a pulsed DC bias. Finally, we describe how the remaining components of an all-acoustic radiofrequency signal processor are an extension of this work.

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Nanoantenna-Enhanced Resonant Detectors for Improved Infrared Detector Performance

Goldflam, Michael G.; Anderson, Evan M.; Fortune, Torben R.; Klem, John F.; Hawkins, Samuel D.; Davids, Paul D.; Campione, Salvatore; Pung, Aaron J.; Webster, Preston T.; Weiner, Phillip H.; Finnegan, Patrick S.; Wendt, Joel R.; Wood, Michael G.; Haines, Chris H.; Coon, Wesley T.; Olesberg, Jonathon T.; Shaner, Eric A.; Kadlec, Clark N.; Beechem, Thomas E.; Sinclair, Michael B.; Tauke-Pedretti, Anna; Kim, Jin K.; Peters, D.W.

Abstract not provided.

Monolithically fabricated tunable long-wave infrared detectors based on dynamic graphene metasurfaces

Applied Physics Letters

Goldflam, Michael G.; Ruiz, Isaac R.; Howell, S.W.; Tauke-Pedretti, Anna; Anderson, Evan M.; Wendt, J.R.; Finnegan, P.; Hawkins, Samuel D.; Coon, W.; Fortune, Torben R.; Shaner, Eric A.; Kadlec, Clark N.; Olesberg, Jonathon T.; Klem, John F.; Webster, Preston T.; Sinclair, Michael B.; Kim, Jin K.; Peters, D.W.; Beechem, Thomas E.

Here, the design, fabrication, and characterization of an actively tunable long-wave infrared detector, made possible through direct integration of a graphene-enabled metasurface with a conventional type-II superlattice infrared detector, are reported. This structure allows for post-fabrication tuning of the detector spectral response through voltage-induced modification of the carrier density within graphene and, therefore, its plasmonic response. These changes modify the transmittance through the metasurface, which is fabricated monolithically atop the detector, allowing for spectral control of light reaching the detector. Importantly, this structure provides a fabrication-controlled alignment of the metasurface filter to the detector pixel and is entirely solid-state. Using single pixel devices, relative changes in the spectral response exceeding 8% have been realized. These proof-of-concept devices present a path toward solid-state hyperspectral imaging with independent pixel-to-pixel spectral control through a voltage-actuated dynamic response.

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Active and Nonreciprocal Radio-Frequency Acoustic Microsystems

Hackett, Lisa A.; Siddiqui, Aleem M.; Dominguez, Daniel D.; Douglas, James K.; Tauke-Pedretti, Anna; Friedmann, Thomas A.; Peake, Gregory M.; Arterburn, Shawn C.; Miller, Michael R.; Eichenfield, Matthew S.

Radio frequency (RF) devices are becoming more multi-band, increasing the number of filters and other front-end components while simultaneously pushing towards reduced cost, size, weight, and power (CSWaP). One approach to reducing CSWaP is to augment the achievable functionalities of electromechanical/acoustic filtering chips to include "active" and nonlinear functionalities, such as gain and mixing. The acoustoelectric (AE) effect could enable such active acoustic wave devices. We have examined the AE effect with a leaky surface acoustic wave (LSAW) in a monolithic structure of epitaxial indium gallium arsenide (In GaAs) on lithium niobate (LiNb0 3 ). This lead to experimentally demonstrated state-of-the-art SAW amplifier performance in terms of gain per acoustic wavelength, reduced power consumption, and increased power efficiency. We quantitatively compare the amplifier performance to previous notable works and discuss the outlook of active acoustic wave components using this material platform. Ultimately, this could lead to smaller, higher-performance RF signal processors for communications applications.

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High-gain leaky surface acoustic wave amplifier in epitaxial InGaAs on lithium niobate heterostructure

Applied Physics Letters

Hackett, L.; Siddiqui, A.; Dominguez, Daniel D.; Douglas, James K.; Tauke-Pedretti, Anna; Friedmann, Thomas A.; Peake, G.; Arterburn, Shawn C.; Eichenfield, Matthew S.

Active surface acoustic wave components have the potential to transform RF front ends by consolidating functionalities that currently occur across multiple chip technologies, leading to reduced insertion loss from converting back and forth between acoustic and electronic domains in addition to improved size and power efficiency. This letter demonstrates a significant advance in these active devices with a compact, high-gain, and low-power leaky surface acoustic wave amplifier based on the acoustoelectric effect. Devices use an acoustically thin semi-insulating InGaAs surface film on a YX lithium niobate substrate to achieve exceptionally high acoustoelectric interaction strength via an epitaxial In0.53Ga0.47As(P)/InP quaternary layer structure and wafer-scale bonding. We demonstrate 1.9 dB of gain per acoustic wavelength and power consumption of 90 mW for 30 dB of electronic gain. Despite the strong intrinsic leaky propagation loss, 5 dB of terminal gain is obtained for a semiconductor that is only 338 μm long due to state-of-the-art heterogenous integration and an improved material platform.

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Large Acoustoelectric Effect in Wafer Bonded Indium Gallium Arsenide / Lithium Niobate Heterostructure Augmented by Novel Gate Control

2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII

Siddiqui, Aleem M.; Hackett, Lisa A.; Dominguez, Daniel D.; Tauke-Pedretti, Anna; Friedmann, Thomas A.; Peake, Gregory M.; Miller, Michael R.; Douglas, James K.; Eichenfield, Matthew S.

This paper demonstrates a monolithic surface acoustic wave amplifier fabricated by state-of-the-art heterogenous integration of a IH-V InGaAs-based epitaxial material stack and LiNb03. Due to the superior properties of the materials employed, we observe electron gain and also non-reciprocal gain in excess of 30dB with reduced power consumption. Additionally, we present a framework for performance optimization as a function of material parameters for a targeted gain. This platform enables further advances in active and non-reciprocal piezoelectric acoustic devices.

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Demonstration of a 9 kV reverse breakdown and 59 mΩ-cm2 specific on-resistance AlGaN/GaN Schottky barrier diode

Solid-State Electronics

Colón, Albert; Douglas, Erica A.; Pope, Andrew J.; Klein, Brianna A.; Stephenson, Chad A.; Van Heukelom, Michael V.; Tauke-Pedretti, Anna; Baca, A.G.

Al0.26Ga0.74N/GaN on SiC lateral Schottky diodes were fabricated with variable anode-to-cathode spacing and were analyzed for blocking and on-state device performance. On-chip normally-on High Electron Mobility Transistor (HEMT) structures were also fabricated for a comparison of blocking characteristics. The Schottky diode displayed an ideality factor of 1.59 with a Ni/AlGaN zero bias barrier height of 1.18 eV and a flat band barrier height of 1.59 eV. For anode-to-cathode spacings between 10 and 100 μm, an increase in median breakdown voltages from 529 V to 8519 V and median specific on-resistance (Ron-sp) from 1.5 to 60.7 mΩ cm2 was observed with an increase in spacing. The highest performing diode had a lateral figure of merit of 1.37 GW/cm2 corresponding to a breakdown voltage upwards of 9 kV and a Ron-sp of 59 mΩ cm2. This corresponds to the highest Schottky diode breakdown voltage reported thus far with an Al0.26Ga0.74N/GaN lateral structure.

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TCAD simulation of a 1 kV 10 A GaN MISFET Device

Dickerson, Jeramy R.; Dickerson, Jeramy R.; Dickerson, Jeramy R.; Dickerson, Jeramy R.; Kaplar, Robert K.; Kaplar, Robert K.; Kaplar, Robert K.; Kaplar, Robert K.; Tauke-Pedretti, Anna; Tauke-Pedretti, Anna; Tauke-Pedretti, Anna; Tauke-Pedretti, Anna; Armstrong, Andrew A.; Armstrong, Andrew A.; Armstrong, Andrew A.; Armstrong, Andrew A.; Crawford, Mary H.; Crawford, Mary H.; Crawford, Mary H.; Crawford, Mary H.; Allerman, A.A.; Allerman, A.A.; Allerman, A.A.; Allerman, A.A.; Pickrell, Gregory P.; Pickrell, Gregory P.; Pickrell, Gregory P.; Pickrell, Gregory P.

Abstract not provided.

Hybrid Integration of III-V Solar Microcells for High-Efficiency Concentrated Photovoltaic Modules

IEEE Journal of Selected Topics in Quantum Electronics

Tauke-Pedretti, Anna; Cederberg, Jeffrey G.; Cruz-Campa, Jose L.; Alford, Charles A.; Sanchez, Carlos A.; Nielson, Gregory N.; Okandan, Murat; Sweatt, W.C.; Jared, Bradley H.; Saavedra, Michael; Miller, William; Keeler, Gordon A.; Paap, Scott M.; Mudrick, John; Lentine, Anthony; Resnick, Paul; Gupta, Vipin; Nelson, Jeffrey; Li, Lan; Li, Duanhui; Gu, Tian; Hu, Juejun

The design, fabrication, and performance of InGaAs and InGaP/GaAs microcells are presented. These cells are integrated with a Si wafer providing a path for insertion in hybrid concentrated photovoltaic modules. Comparisons are made between bonded cells and cells fabricated on their native wafer. The bonded cells showed no evidence of degradation in spite of the integration process that involved significant processing including the removal of the III-V substrate.

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Integrating Resonant Structures with IR Detectors

Goldflam, Michael G.; Goldflam, Michael G.; Anderson, Evan M.; Anderson, Evan M.; Campione, Salvatore; Campione, Salvatore; Coon, Wesley T.; Coon, Wesley T.; Davids, Paul D.; Davids, Paul D.; Fortune, Torben R.; Fortune, Torben R.; Hawkins, Samuel D.; Hawkins, Samuel D.; Kadlec, Clark N.; Kadlec, Clark N.; Kadlec, Emil A.; Kadlec, Emil A.; Kim, Jin K.; Kim, Jin K.; Klem, John F.; Klem, John F.; Shaner, Eric A.; Shaner, Eric A.; Sinclair, Michael B.; Sinclair, Michael B.; Tauke-Pedretti, Anna; Tauke-Pedretti, Anna; Warne, Larry K.; Warne, Larry K.; Wendt, J.R.; Wendt, J.R.; Beechem, Thomas E.; Beechem, Thomas E.; Howell, Stephen W.; Howell, Stephen W.; McDonald, Anthony E.; McDonald, Anthony E.; Ruiz, Isaac R.; Ruiz, Isaac R.

Abstract not provided.

Improved infrared detection using nanoantennas

International Conference on Optical MEMS and Nanophotonics

Peters, D.W.; Sinclair, Michael B.; Goldflam, Michael G.; Warne, Larry K.; Campione, Salvatore; Kim, Jin K.; Davids, Paul D.; Tauke-Pedretti, Anna; Wendt, J.R.; Klem, John F.; Hawkins, Samuel D.; Parameswaran, Sivasubramanian P.; Coon, W.T.; Keeler, G.A.; Fortune, Torben R.

We examine integration of a patterned metal nanoantenna (or metasurface) directly onto long-wave infrared detectors. These structures show significantly improved external quantum efficiency compared to their traditional counterparts. We will show simulation and experimental results.

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Resonantly enhanced infrared detectors based on type-II superlattice absorbers

Goldflam, Michael G.; Goldflam, Michael G.; Campione, Salvatore; Campione, Salvatore; Kadlec, Emil A.; Kadlec, Emil A.; Hawkins, Samuel D.; Hawkins, Samuel D.; Coon, Wesley T.; Coon, Wesley T.; Fortune, Torben R.; Fortune, Torben R.; Parameswaran, Sivasubramanian P.; Parameswaran, Sivasubramanian P.; Keeler, Gordon A.; Keeler, Gordon A.; Klem, John F.; Klem, John F.; Tauke-Pedretti, Anna; Tauke-Pedretti, Anna; Shaner, Eric A.; Shaner, Eric A.; Davids, Paul D.; Davids, Paul D.; Warne, Larry K.; Warne, Larry K.; Wendt, J.R.; Wendt, J.R.; Kim, Jin K.; Kim, Jin K.; Peters, D.W.; Peters, D.W.

Abstract not provided.

Next-generation infrared focal plane arrays for high-responsivity low-noise applications

IEEE Aerospace Conference Proceedings

Goldflam, Michael G.; Hawkins, Samuel D.; Parameswaran, Sivasubramanian P.; Tauke-Pedretti, Anna; Warne, Larry K.; Peters, D.W.; Campione, Salvatore; Coon, W.T.; Keeler, Gordon A.; Shaner, Eric A.; Wendt, J.R.; Kadlec, Emil A.; Fortune, Torben R.; Klem, John F.; Davids, Paul D.; Kim, Jin K.

High-quality infrared focal plane arrays (FPAs) are used in many satellite, astronomical, and terrestrial applications. These applications require highly-sensitive, low-noise FPAs, and therefore do not benefit from advances made in low-cost thermal imagers where reducing cost and enabling high-temperature operation drive device development. Infrared detectors used in FPAs have been made for decades from alloys of mercury cadmium telluride (MCT). These infrared detectors are nearing the believed limit of their performance. This limit, known in the infrared detector community as Rule 07, dictates the dark current floor for MCT detectors, in their traditional architecture, for a given temperature and cutoff wavelength. To overcome the bounds imposed by Rule 07, many groups are working on detector compounds other than MCT. We focus on detectors employing III-V-based gallium-free InAsSb superlattice active regions while also changing the basic architecture of the pixel to improve signal-to-noise. Our architecture relies on a resonant, metallic, subwavelength nanoantenna patterned on the absorber surface, in combination with a Fabry-Pérot cavity, to couple the incoming radiation into tightly confined modes near the nanoantenna. This confinement of the incident energy in a thin layer allows us to greatly reduce the volume of the absorbing layer to a fraction of the free-space wavelength, yielding a corresponding reduction in dark current from spontaneously generated electron-hole pairs in the absorber material. This architecture is detector material agnostic and could be applied to MCT detector structures as well, although we focus on using superlattice antimonide-based detector materials. This detector concept has been applied to both mid-wave (3-5 μm) and longwave (8-12 μm) infrared detectors and absorbers. Here we examine long-wave devices, as these detectors currently have a larger gap between desired device performance and that of currently existing detectors. The measured structures show an external quantum efficiency exceeding 50%. We present a comparison of the modeled and measured photoresponse of these detectors and compare these detectors to currently available commercial detectors using relevant metrics such as external quantum efficiency. We also discuss modeling of crosstalk between adjacent pixels and its influence on the potential for a dual-wavelength detector. Finally, we evaluate potential advances in these detectors that may occur in the near future.

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Enhanced infrared detectors using resonant structures combined with thin type-II superlattice absorbers

Applied Physics Letters

Goldflam, Michael G.; Kadlec, Emil A.; Olson, B.V.; Klem, John F.; Hawkins, Samuel D.; Parameswaran, Sivasubramanian P.; Coon, W.T.; Keeler, Gordon A.; Fortune, Torben R.; Tauke-Pedretti, Anna; Wendt, J.R.; Shaner, Eric A.; Davids, Paul D.; Kim, Jin K.; Peters, D.W.

We examined the spectral responsivity of a 1.77 μm thick type-II superlattice based long-wave infrared detector in combination with metallic nanoantennas. Coupling between the Fabry-Pérot cavity formed by the semiconductor layer and the resonant nanoantennas on its surface enables spectral selectivity, while also increasing peak quantum efficiency to over 50%. Electromagnetic simulations reveal that this high responsivity is a direct result of field-enhancement in the absorber layer, enabling significant absorption in spite of the absorber's subwavelength thickness. Notably, thinning of the absorbing material could ultimately yield lower photodetector noise through a reduction in dark current while improving photocarrier collection efficiency. The temperature- and incident-angle-independent spectral response observed in these devices allows for operation over a wide range of temperatures and optical systems. This detector paradigm demonstrates potential benefits to device performance with applications throughout the infrared.

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Compound semiconductor integrated photonics for avionics

2016 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference, AVFOP 2016

Tauke-Pedretti, Anna

This talk will focus on recent work done at Sandia National Laboratories in compound semiconductor integrated photonics relevant to avionics. Two technologies will be presented: Sandia's InP-based photonic integrated circuit platform which enables highly functional circuits and advanced heterogenous integration for microscale photovoltaic systems.

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Compound Semiconductor Integrated Photonics for Avionics

Tauke-Pedretti, Anna; Vawter, Gregory A.; Skogen, Erik J.; Alford, Charles A.; Cajas, Florante G.; Overberg, Mark E.; Peake, Gregory M.; Wendt, J.R.; Chow, Weng W.; Lentine, Anthony L.; Nelson, Jeffrey S.; Sweatt, W.C.; Jared, Bradley H.; Resnick, Paul J.; Sanchez, Carlos A.; Pipkin, Jennifer R.; Girard, Gerald R.; Nielson, Greg N.; Cruz-Campa, Jose L.; Okandan, Murat O.

Abstract not provided.

Wavelength Conversion Arrays for Optical and X-Ray Diagnostics at Z

Skogen, Erik J.; Dolan, Daniel H.; Vawter, Gregory A.; Tauke-Pedretti, Anna; Peake, Gregory M.; Alford, Charles A.; Cajas, Florante G.

Optical diagnostics play a central role in dynamic compression research. Currently, streak cameras are employed to record temporal and spectroscopic information in single-event experiments, yet are limited in several ways; the tradeoff between time resolution and total record duration is one such limitation. This project solves the limitations that streak cameras impose on dynamic compression experiments while reducing both cost and risk (equipment and labor) by utilizing standard high-speed digitizers and commercial telecommunications equipment. The missing link is the capability to convert the set of experimental (visible/x-ray) wavelengths to the infrared wavelengths used in telecommunications. In this report, we describe the problem we are solving, our approach, our results, and describe the system that was delivered to the customer. The system consists of an 8-channel visible-to- infrared converter with > 2 GHz 3-dB bandwidth.

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Thermal Design and Characterization of Heterogeneously Integrated InGaP/GaAs HBTs

IEEE Transactions on Components, Packaging and Manufacturing Technology

Choi, Sukwon; Peake, Gregory M.; Keeler, Gordon A.; Geib, K.M.; Briggs, R.D.; Beechem, Thomas E.; Shaffer, Ryan A.; Clevenger, Jascinda C.; Patrizi, G.A.; Klem, John F.; Tauke-Pedretti, Anna; Nordquist, Christopher N.

Flip-chip heterogeneously integrated n-p-n InGaP/GaAs heterojunction bipolar transistors (HBTs) with integrated thermal management on wide-bandgap AlN substrates followed by GaAs substrate removal are demonstrated. Without thermal management, substrate removal after integration significantly aggravates self-heating effects, causing poor $I$-$V$ characteristics due to excessive device self-heating. An electrothermal codesign scheme is demonstrated that involves simulation (design), thermal characterization, fabrication, and evaluation. Thermoreflectance thermal imaging, electrical-temperature sensitive parameter-based thermometry, and infrared thermography were utilized to assess the junction temperature rise in HBTs under diverse configurations. In order to reduce the thermal resistance of integrated devices, passive cooling schemes assisted by structural modification, i.e., positioning indium bump heat sinks between the devices and the carrier, were employed. By implementing thermal heat sinks in close proximity to the active region of flip-chip integrated HBTs, the junction-to-baseplate thermal resistance was reduced over a factor of two, as revealed by junction temperature measurements and improvement of electrical performance. The suggested heterogeneous integration method accounts for not only electrical but also thermal requirements providing insight into realization of advanced and robust III-V/Si heterogeneously integrated electronics.

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Microsystem Enabled Photovoltaics

Nielson, Gregory N.; Cruz Campa, Jose L.; Okandan, Murat O.; Lentine, Anthony L.; Sweatt, W.C.; Gupta, Vipin P.; Tauke-Pedretti, Anna; Jared, Bradley H.; Resnick, Paul J.; Cederberg, Jeffrey G.; Paap, Scott M.; Sanchez, Carlos A.; Biefeld, Robert M.; Langlois, Eric L.; Yang, Benjamin B.; Koleske, Daniel K.; Wierer, Jonathan J.; Miller, William K.; Elisberg, Brenton E.; Zamora, David J.; Luna, Ian L.; Saavedra, Michael P.; Alford, Charles A.; Ballance, Mark H.; Wiwi, Michael W.; Samora, S.; Chavez, Julie C.; Pipkin, Jennifer R.; Nguyen, Janet N.; Anderson, Ben A.; Gu, Tian G.; Agrawal, Gautum A.; Nelson, Jeffrey S.

Abstract not provided.

Minority carrier lifetime and dark current measurements in mid-wavelength infrared InAs0.91Sb0.09 alloy nBn photodetectors

Applied Physics Letters

Olson, B.V.; Kim, Jin K.; Kadlec, Emil A.; Klem, John F.; Hawkins, Samuel D.; Leonhardt, Darin L.; Coon, W.T.; Fortune, Torben R.; Cavaliere, Melissa A.; Tauke-Pedretti, Anna; Shaner, Eric A.

Carrier lifetime and dark current measurements are reported for a mid-wavelength infrared InAs0.91Sb0.09 alloy nBn photodetector. Minority carrier lifetimes are measured using a non-contact time-resolved microwave technique on unprocessed portions of the nBn wafer and the Auger recombination Bloch function parameter is determined to be |F1F2|=0.292. The measured lifetimes are also used to calculate the expected diffusion dark current of the nBn devices and are compared with the experimental dark current measured in processed photodetector pixels from the same wafer. Excellent agreement is found between the two, highlighting the important relationship between lifetimes and diffusion currents in nBn photodetectors.

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Selective layer disordering in intersubband Al0.028Ga0.972 N/AlN superlattices with silicon nitride capping layer

Applied Physics Express

Wierer Jr, Jonathan W.; Allerman, A.A.; Skogen, Erik J.; Tauke-Pedretti, Anna; Vawter, Gregory A.; Montano, Ines M.

We demonstrate the selective layer disordering in intersubband Al0.028Ga0.972 N/AlN superlattices using a silicon nitride (SiNx) capping layer. The (SiNx) capped superlattice exhibits suppressed layer disordering under high-temperature annealing. In addition, the rate of layer disordering is reduced with increased SiNx thickness. The layer disordering is caused by Si diffusion, and the SiNx layer inhibits vacancy formation at the crystal surface and ultimately, the movement of Al and Ga atoms across the heterointerfaces. In conclusion, patterning of the SiNx layer results in selective layer disordering, an attractive method to integrate active and passive III–nitride-based intersubband devices.

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Photonic integration at sandia national laboratories

Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2015

Tauke-Pedretti, Anna; Vawter, Gregory A.; Skogen, Erik J.; Alford, Charles A.; Overberg, Mark E.; Peake, Gregory M.; Cajas, Florante G.

This talk will discuss recent work on photonic integration for applications in optical signal processing, digital logic, and fundamental device research with an emphasis on InP-based photonic integrated circuit technology. © 2015 OSA.

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Cost analysis of flat-plate concentrators employing microscale photovoltaic cells for high energy per unit area applications

2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014

Paap, Scott; Gupta, Vipin P.; Tauke-Pedretti, Anna; Resnick, Paul J.; Sanchez, Carlos A.; Nielson, Gregory N.; Cruz-Campa, Jose L.; Jared, Bradley H.; Nelson, Jeffrey; Okandan, Murat O.; Sweatt, W.C.

Microsystems Enabled Photovoltaics (MEPV) is a relatively new field that uses microsystems tools and manufacturing techniques familiar to the semiconductor industry to produce microscale photovoltaic cells. The miniaturization of these PV cells creates new possibilities in system designs that can be used to reduce costs, enhance functionality, improve reliability, or some combination of all three. In this article, we introduce analytical tools and techniques to estimate the costs associated with a hybrid concentrating photovoltaic system that uses multi-junction microscale photovoltaic cells and miniaturized concentrating optics for harnessing direct sunlight, and an active c-Si substrate for collecting diffuse sunlight. The overall model comprises components representing costs and profit margin associated with the PV cells, concentrating optics, balance of systems, installation, and operation. This article concludes with an analysis of the component costs with particular emphasis on the microscale PV cell costs and the associated tradeoffs between cost and performance for the hybrid CPV design.

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Layer disordering and doping compensation of an intersubband AlGaN/AlN superlattice by silicon implantation

Applied Physics Letters

Wierer, J.J.; Allerman, A.A.; Skogen, Erik J.; Tauke-Pedretti, Anna; Alford, Charles A.; Vawter, Gregory A.; Montano, Ines M.

Layer disordering and doping compensation of an Al0.028Ga0.972N/AlN superlattice by implantation are demonstrated. The as-grown sample exhibits intersubband absorption at ∼1.56 μm which is modified when subject to a silicon implantation. After implantation, the intersubband absorption decreases and shifts to longer wavelengths. Also, with increasing implant dose, the intersubband absorption decreases. It is shown that both layer disordering of the heterointerfaces and doping compensation from the vacancies produced during the implantation cause the changes in the intersubband absorption. Such a method is useful for removing absorption in spatially defined areas of III-nitride optoelectronic devices by, for example, creating low-loss optical waveguides monolithically that can be integrated with as-grown areas operating as electro-absorption intersubband modulators.

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Flat plate concentrators with large acceptance angle enabled by micro cells and mini lenses: performance evaluation

Cruz-Campa, Jose L.; Anderson, Benjamin J.; Gupta, Vipin P.; Tauke-Pedretti, Anna; Cederberg, Jeffrey G.; Paap, Scott M.; Sanchez, Carlos A.; Nordquist, Christopher N.; Nielson, Gregory N.; Saavedra, Michael P.; Ballance, Mark H.; Nguyen, Janet N.; Alford, Charles A.; Riley, Daniel R.; Okandan, Murat O.; Lentine, Anthony L.; Sweatt, W.C.; Jared, Bradley H.; Resnick, Paul J.; Kratochvil, Jay A.

Abstract not provided.

Advanced compound semiconductor and silicon fabrication techniques for next-generation solar power systems

ECS Transactions

Nielson, Gregory N.; Okandan, Murat O.; Cruz-Campa, Jose L.; Gupta, Vipin P.; Resnick, Paul J.; Sanchez, Carlos A.; Paap, Scott M.; Kim, B.; Sweatt, W.C.; Lentine, Anthony L.; Cederberg, Jeffrey G.; Tauke-Pedretti, Anna; Jared, B.H.; Anderson, Benjamin J.; Biefeld, Robert M.; Nelson, J.S.

Microsystem technologies have the potential to significantly improve the performance, reduce the cost, and extend the capabilities of solar power systems. These benefits are possible due to a number of significant beneficial scaling effects within solar cells, modules, and systems that are manifested as the size of solar cells decrease to the sub-millimeter range. To exploit these benefits, we are using advanced fabrication techniques to create solar cells from a variety of compound semiconductors and silicon that have lateral dimensions of 250 - 1000 μm and are 1 - 20 μm thick. These fabrication techniques come out of relatively mature microsystem technologies such as integrated circuits (IC) and microelectromechanical systems (MEMS) which provide added supply chain and scale-up benefits compared to even incumbent PV technologies. © The Electrochemical Society.

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Wide dynamic range of ring resonator channel-dropping filters with integrated SOAs

Optics InfoBase Conference Papers

Vawter, Gregory A.; Tauke-Pedretti, Anna; Skogen, Erik J.

We present the first complete simulation of the dynamic range and noise of InGaAsP multi-ring channel-drop filters with internal SOAs. The results show gain saturation, and spontaneous emission noise limit the dynamic range. © 2010 Optical Society of America.

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Wide dynamic range of ring resonator channel-dropping filters with integrated SOAs

2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2011

Vawter, Gregory A.; Tauke-Pedretti, Anna; Skogen, Erik J.

We present the first complete simulation of the dynamic range and noise of InGaAsP multi-ring channel-drop filters with internal SOAs. The results show gain saturation, and spontaneous emission noise limit the dynamic range. © 2011 Optical Society of America.

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Optical logic gates using interconnected photodiodes and electro-absorption modulators

Optics InfoBase Conference Papers

Skogen, Erik J.; Vawter, Gregory A.; Tauke-Pedretti, Anna; Overberg, Mark E.; Peake, Gregory M.; Alford, Charles; Torres, David; Cajas, Florante; Sullivan, Charles T.

We demonstrate an optical gate architecture with optical isolation between input and output using interconnected PD-EAMs to perform AND and NOT functions. Waveforms for 10 Gbps AND and 40 Gbps NOT gates are shown. © 2010 Optical Society of America.

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70 Results
70 Results