Next-Generation Infrared Focal Plane Arrays for High-Responsivity Low-Noise Applications
Abstract not provided.
Publications
Wafer-level Integrated Micro-scale Concentrating Photovoltaics
Abstract not provided.
Wafer-level Integrated Concentrating Photovoltaics (Annual Meeting)
Abstract not provided.
Enhanced infrared detectors using resonant structures combined with thin type-II superlattice absorbers
Applied Physics Letters
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.
Compound semiconductor integrated photonics for avionics
2016 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference, AVFOP 2016
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.
Compound Semiconductor Integrated Photonics for Avionics
Abstract not provided.
Wavelength Conversion Arrays for Optical and X-Ray Diagnostics at Z
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.
Nanoantenna-Enhanced Infrared Detectors for Improved Performance and Spectral Tunability
Abstract not provided.
Thermal Design and Characterization of Heterogeneously Integrated InGaP/GaAs HBTs
IEEE Transactions on Components, Packaging and Manufacturing Technology
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.
Compound semiconductor integrated photonics at Sandia National Laboratories
Abstract not provided.
Microsystem Enabled Photovoltaics
Abstract not provided.
Wafer-level Integrated Micro-scale Concentrating Photovoltaics
Abstract not provided.
AlGaAs Photon Pair Sources
Abstract not provided.
Micro-Chiplet Printer for MOSAIC
Abstract not provided.
Micro-Chiplet Printer for MOSAIC
Abstract not provided.
Minority carrier lifetime and dark current measurements in mid-wavelength infrared InAs0.91Sb0.09 alloy nBn photodetectors
Applied Physics Letters
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.
Compound Semiconductor Photonic Integrated Circuits at Sandia National Laboratories
Abstract not provided.
Photonic Integration at Sandia National Laboratories
Abstract not provided.
Strain-Mediated Interfacial Diffusion and Shifts in ISB Transition Energies in AlN/AlGaN Superlattices
Abstract not provided.
Microscopic modeling of nitride intersubband absorption
Abstract not provided.
Selective layer disordering in intersubband Al0.028Ga0.972 N/AlN superlattices with silicon nitride capping layer
Applied Physics Express
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.
Integrating III-V compound semiconductors with silicon for advanced multijunction solar cells
Abstract not provided.
Photonic integration at sandia national laboratories
Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2015
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.
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
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.
Layer disordering and doping compensation of an intersubband AlGaN/AlN superlattice by silicon implantation
Applied Physics Letters
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.
Results 26–50 of 70