Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session M34: Photodetectors and Optical Emitters |
Hide Abstracts |
Sponsoring Units: FIAP Chair: Jay Mathews, University of Dayton Room: Room 226/227 |
Wednesday, March 8, 2023 8:00AM - 8:12AM |
M34.00001: A Self-Similar Sine-Cosine Fractal Architecture for Multiport Interferometers Jasvith Basani, Sri Krishna Vadlamani, Saumil Bandyopadhyay, Dirk R Englund, Ryan Hamerly Integrated photonic architectures based on beamsplitter meshes have recently captured attention as a platform to accelerate many conventional computing tasks. Among these tasks, one that is fundamental to linear algebra and neural networks is matrix processing. We propose a novel architecture for multiport interferometric meshes based on the Sine-Cosine Fractal (SCF) decomposition of unitary matrices to implement arbitrary linear matrix transforms. The design we propose is unique in that it is self-similar, thus enabling the construction of large-scale modular multi-chiplet devices. We find that this modularity dictates the distribution of phase-shifts in the SCF mesh, due to which our design enjoys improved resilience to hardware imperfections as compared to conventional multiport interferometers. Additionally, the structure of this circuit enables systematic truncation, which is key in reducing the hardware footprint of the device, as well as training time for use in optical neural networks. Via numerical simulations, we show that truncated meshes maintain robust performance even under large fabrication errors, which is commensurate with present-day digital electronic deep neural network accelerators. This design is a step forward in the construction of large-scale programmable photonics, opening up prospects of scaling to practical machine learning and quantum computing applications. |
Wednesday, March 8, 2023 8:12AM - 8:24AM |
M34.00002: Raman spectroscopy in open world learning settings using the Objectosphere approach Yaroslav Balytskyi Raman spectroscopy, combined with machine learning techniques, holds great promise for many applications as a rapid, sensitive, and label-free identification method. Such approaches perform well when classifying spectra of chemical species that were encountered during the training phase. That is, species that are known to the neural network. However, in real-world settings such as in clinical applications, there will always be substances whose spectra have not yet been taken. When the neural network encounters these new species during the testing phase, the number of false positives becomes uncontrollable, limiting the usefulness of these techniques, especially in public safety applications. |
Wednesday, March 8, 2023 8:24AM - 8:36AM |
M34.00003: Plasmon Enhanced Multi-Photon Excited Photoluminescence of Nobel Metal Nanoclusters Jhovani Enrique Bornacelli-Camargo, Carlos Torres-Torres, Alejandro Crespo-Sosa, Jorge-Alejandro Reyes-Esqueda, Alicia Oliver In the last decade, metal nanoclusters (ncs) have emerged as a new kind of efficient nano-emitters with an ultra-small size (less than 2 nm), and tunable emission ranging from visible to infrared wavelengths. Multi-Photon Excited Photoluminescence (MPEPL) has also been observed from Au clusters and their impactful application in nanoscale photonic devices has also been pointed out. In this work, we have studied the MPEPL from metal nanoclusters (Au, Ag, and Pt) embedded in Al2O3 matrix by ion implantation. The thermal annealing process allows us to obtain a system composed of larger plasmonic metal nanoparticles (nps) surrounded by photoluminescent ultra-small metal ncs. The excitation wavelength used was of 1064 nm, and emissions occur at visible wavelength, ranging from 450 to 800 nm. The second and fourth-order nature of the MPEPL was verified in a power-dependent study below the damage threshold measured for each sample: 58 and 77 GW/cm2 for Ag and Au nanocomposites, respectively. Our experiments show that Au and Ag ncs exhibit greater MPEPL than that observed for Pt ncs, which can be explained as a result of a plasmon-mediated optical process of less intensity for Pt nps. These findings provide new opportunities to combine plasmonic nps and photoluminescent ncs inside a robust inorganic matrix to improve their optical properties. Plasmon-enhanced MPEPL from metal ncs may find potential application as ultrasmall fluorophores in multiphoton sensing, and also in the development of solar cells with highly efficient energy conversion modules. |
Wednesday, March 8, 2023 8:36AM - 8:48AM |
M34.00004: Achieving bright light emission across the spectrum with pulsed electroluminescent devices Vivian Wang, Ali Javey The scope of luminescent materials used in light-emitting devices is often limited by material processing and band alignment concerns. We have developed a capacitive device structure with a single injection contact which can generate bright electroluminescence from a wide range of materials, simply by depositing the luminescent material on top of the device. Charge injection is achieved across different band alignments by applying pulsed voltages across the metal-oxide-semiconductor capacitor structure. By using carbon nanotube networks as the injection contact, emission can be produced from vast libraries of nanomaterials across the ultraviolet to infrared energy range without additional charge injection layers. Light emission can be observed at high frequencies at voltages near the optical gap of the emissive material by employing a thin high-k gate oxide layer. Due to the compatibility of the device with non-uniform and arbitrarily shaped active layers, scalable fabrication of large device arrays can be achieved. Multiplexed electroluminescent arrays with emission spanning a broad spectral range may enable new opportunities in optoelectronics and spectral measurement, of which a few examples are discussed. |
Wednesday, March 8, 2023 8:48AM - 9:00AM |
M34.00005: High temperature operation of p-GaN/AlGaN/GaN based devices Hanwool Lee, Hojoon Ryu, Wenjuan Zhu P-GaN/AlGaN/GaN heterostructure has gained great interest for the feasibility of both n-channel and p-channel devices. Since gallium nitride has large bandgap, high breakdown field, low intrinsic carrier concentration, and high thermal stability, it has huge potential for high temperature electronics as well. In this study, both n-channel and p-channel devices were fabricated on the p-GaN/AlGaN/GaN platform and measured at high temperatures. N-channel device showed stable normally-off operation, since the p-GaN layer depletes the 2D electron gas (2-DEG) in the GaN channel. The p-channel device showed scalability of the threshold voltage depending on the depth of the p-GaN recess. At high temperatures up to 500 °C, n-channel device showed stable threshold voltage, although the on-current decreased slightly due to the degraded 2DEG mobility when temperature exceeds 400 °C. In contrast, D-mode p-channel device showed slight threshold voltage shift towards the negative direction and an increment of the on-current when temperature increases from room temperature to 500 °C. Inverters based on p-channel and n-channel devices are demonstrated, which show stable logic threshold voltage and high gain up to 500 °C. These high temperature devices and circuits will have broad applications in automotive, geothermal, avionics and aerospace. |
Wednesday, March 8, 2023 9:00AM - 9:12AM |
M34.00006: A model for the I-V characteristics of Ge and GeSn epitaxial pin diodes Jose Menendez, Matthew A Mircovich, John Kouvetakis A quantitative model is presented for the I-V characteristics of GeSn pin diodes. GeSn alloys, with band gaps ranging between those of pure Ge and zero, are viewed as intriguing Si-compatible alternatives for infrared applications. This has motivated sustained efforts to understand the properties of GeSn devices. |
Wednesday, March 8, 2023 9:12AM - 9:24AM |
M34.00007: Spectral Optical Responsivity of GeSn PIN Diodes: Experiment and Theory Matthew A Mircovich, Jose Menendez, John Kouvetakis, Dhruve Ringwala, Aixin Zhang, Chi Xu Homostructure GeSn pin diodes were grown on Ge-buffered Si substrates by a combination of ultra-high-vacuum chemical vapor deposition (UHV-CVD) and gas-source molecular epitaxy (GSME). Stannane (SnD4, SnH4) was used as the Sn source and polygermanes (Ge3H8, Ge4H10) as the Ge sources. In-situ doping was made possible by the use of additional precursors containing group-III and group-V atoms, such as P(GeH3)3 or B2H6. The spectral responsivity of the diodes was measured as a function of reverse bias and compared with a model that includes a numerical solution of the semiconductor equations, the effects of multiple reflections and the role of interferences in the optical generation rate, and an accurate calculation of the complex index of refraction for all layers in the structure. The theoretical responsivity values are found to be in excellent agreement with the experimental data. |
Wednesday, March 8, 2023 9:24AM - 9:36AM |
M34.00008: Hyperdoped Si photodetectors for high efficiency and extended conversion range Yining Liu, Wenjie Yang, Jeffrey Warrender, Quentin M Hudspeth, James S Williams, Andrew Sarangan, Imad Agha, Jay A Mathews Hyperdoped silicon is a promising photodetection material with extended infrared response. Supersaturated solutions of impurities in Si are produced to create intermediate bands in between the valence and conduction bands that induce sub-band gap absorption. Ion implantation followed by pulsed laser melting has been demonstrated to produce concentrations of impurities in Si that are well above the solid solubility limit. This method has been used to create photodetectors that show response at wavelengths well beyond the band gap of Si, but the devices demonstrated thus far have been low efficiency. |
Wednesday, March 8, 2023 9:36AM - 9:48AM |
M34.00009: Energy conversion efficiency limits of air-bridge thermophotovoltaic cells Jihun Lim, Byungjun Lee, Bosun Roy-Layinde, Andrej Lenert, Stephen R Forrest The conversion of heat to electricity via thermophotovoltaics (TPVs) holds promise for providing energy storage and recovery for fully decarbonized power grid applications [1,2]. The use of an air-bridge TPV architecture provides a unique method for high energy conversion efficiency with near-perfect out-of-band (OOB) photon reflection (ROOB) [1]. Here we design and demonstrate air-bridge TPV cells using 3-µm-thick InGaAs/InP membranes. From Fourier transform infrared analysis, the cell shows a ROOB > 98.5% at blackbody temperatures of 915–1425K, where the OOB photon loss is less than 1% due to free-carrier absorption. The InGaAs cell shows 17–31% efficiency in this temperature range, compared to a projected maximum efficiency of 31–49%. Using TCAD numerical simulations, we reveal that the efficiency loss is primarily due to surface recombination (with a recombination velocity of 103 cm/s). Finally, we calculate the thermodynamic efficiency limits to the energy conversion efficiency of air-bridge TPVs with different bandgaps and find that the advantage of increasing ROOB increases with bandgap. |
Wednesday, March 8, 2023 9:48AM - 10:00AM |
M34.00010: Moving towards detection of nanoantenna excitation using bandgap agnostic impact ionization sam fedorka, Basil Vanderbie, Charles Dickerson, Kevin A Grossklaus, Thomas Vandervelde, Corey Shemelya As photodetection moves towards longer wavelengths, the semiconductor bandgap (BG) for detection similarly decreases. Eventually this trade-off becomes infeasible as thermally generated carriers begin to overwhelm the expected photocurrent. These thermal effects are exacerbated when utilizing designs such as avalanche photodiodes which require cooling for a small BG design to have low noise. Conversely, a wider BG device enables room-temperature detection at the cost of sensitivity to long wavelength signals. As such, this work overcomes these limitations by decoupling photodetection from semiconductor bandgap using a combination of plasmonic excitation coupled into an avalanche diode with uniquely tuned impact ionization locations. Specifically, we investigate wide band plasmonic nanoantennas, connected to a GaAs avalanche heterostructure with a novel architecture, inspired by phototransistor designs. By tuning the impact ionization locations for the ideal coupling with the nanoantenna, we are able to perform BG agnostic photodetection. The design was simulated with CST Microwave studio plasmonic excitation and COMSOL Multiphysics to simulate impact ionization regions, bias voltages, and output currents. This work presents a novel approach to photodetection which will allow a greater diversity detection schemes, designs, and use-cases. |
Wednesday, March 8, 2023 10:00AM - 10:12AM |
M34.00011: Coherent Acoustic Phonon Oscillations in Ge Using Pump-Probe Time-Resolved Spectroscopic Ellipsometry Carlos A Armenta, Martin Zahradnik, Carola Emminger, Shilry Espinoza, Mateusz Rebarz, Jakob Andreasson, Stefan Zollner Photoexcitation of bulk materials can create hot charge carriers that relax by transferring energy to the lattice, hence exciting phonons in the process. By photoexciting the material through femtosecond laser pulses, coherent acoustic phonon (CAP) oscillations at picosecond time scales are generated via this method. These CAP oscillations are related to an increase in charge carrier density, as well as strain triggered by the laser pulse, however details of this relationship are scarce in the literature. CAP oscillations affect the pseudo-dielectric function (DF) of the material, which makes time-resolved spectroscopic ellipsometry ideal to understand the processes in hand. |
Wednesday, March 8, 2023 10:12AM - 10:24AM |
M34.00012: Nonequilibrium phenomena in bilayer electron systems Sanjeev Kumar, A A Shevyrin, Patrick See, Ian Farrer, David A Ritchie Magnetoresistance of bilayer electron systems with relatively large inter-layer separation shows hysteresis when the filling factor of one of the layers is close to integer values. This hysteresis indicates the absence of equilibrium between the layers [1,2]. In the present work, we performed magnetocapacitance measurements to study the system when both layers are in the quantum Hall effect regime. Results show that the magnetic field sweep drives the system out of equilibrium even when the densities of individual layers are equal, leading to magnetocapacitance hysteresis. This indicates that magnetic field sweep most likely breaks not only inter- but also intra-layer equilibrium. |
Wednesday, March 8, 2023 10:24AM - 10:36AM |
M34.00013: Microscopic Theory of the Magnetic Susceptibility of Insulators Alistair H Duff We present a general theory of the magnetic susceptibility of insulators that can be extended to treat spatially varying and finite frequency fields. We find that for the zero frequency response our method agrees with existing approaches in the literature. We clarify some of the differences that have been noted in the different approaches and prove that in the insulating regime all methods agree with with the identification of various sum rules. We clarify details about the gauge-dependence of the magnetic susceptibility tensor, and prove it is invariant to U(N) gauge transformations. We find that while the theory can be written with diagonal elements of the Berry connection these terms can be repackaged and written as an explicitly gauge-invariant ``geometric" contribution to the magnetic susceptibility that depends on the Abelian Berry curvature. Our formalism identifies a Hermitian spontaneous magnetization matrix element (distinct from existing approaches) which features prominently in the expressions for the susceptibility tensor, and identifies a natural partitioning of the response in terms of atomic and itinerant features in going from the atomic limit to the general insulating crystal. Additionally, we consider an h-BN model to explore some of the features of the magnetic susceptibility tensor and practical considerations for computing. |
Wednesday, March 8, 2023 10:36AM - 10:48AM |
M34.00014: Memristor Behavior in Epitaxial Cu2-xSe Thin Films Becker Sharif, David Lederman Materials with memristor properties are currently of interest because of their applications in neuromorphic circuitry and resistive switching devices. Memristors are suitable for neuromorphic circuitry due to their low energy consumption, high density, and CMOS compatibility. Additionally, low leakage current and high on-to-off current ratios are essential for efficient devices. Non-stoichiometric copper selenide is a promising material that exhibits the above behavior, where the resistive switching is believed to be attributed to the ionic conductivity of copper ions [1]. We will present the room temperature memory resistive behavior of epitaxially grown Cu2-xSe on Al2O3 using Molecular Beam Epitaxy (MBE). The films were characterized using Reflection High Energy Electron Diffraction (RHEED), X-Ray Diffraction (XRD), and Atomic Force Microscopy (AFM). Al interdigitated contacts were used to perform current-voltage (I-V) measurements. The (I-V) measurements showed resistive switching of Cu2-xSe at room temperature with over five orders of magnitude of on-off current ratios.
|
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700