- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Integrated Metamaterial Interfaces for Self-Aligned Fiber-to-Chip Coupling in Volume Manufacturing
摘要： Improving the scalability and cost efficiency of photonic packaging is central to fulfilling the silicon photonic promise of low-cost devices with unprecedented optical complexity. A key enabler towards this goal is an efficient, large-mode, integrated fiber coupler and mode converter. Using standard fiber modes at fiber-to-chip junctions avoids expensive in-fiber mode conversion and relaxes alignment tolerances for low-cost assembly and improved reliability. Metamaterial waveguides, also called subwavelength gratings, are particularly useful for such structures. They provide unmatched design flexibility and, counter-intuitively, are more forgiving to fabrication tolerances than solid-core waveguides. Here, we summarize our work on interfacing self-aligned, standard cleaved fibers to rectangular Si routing waveguides. Fiber V-grooves are integrated on chip with metamaterial converters embedded in suspended oxide membranes to prevent coupler-mode leakage to the substrate. We show optical results from first integration of V-grooves with metamaterial converters to commercial structures fabricated in 300 mm CMOS production facilities. We demonstrate a peak transmission of -0.7 dB on the TE polarization and -1.4 dB on the TM polarization with a respective spectral roll-off of 0.3 and 0.4 dB over the 60 nm bandwidth measured.
关键词： photonic bandgap materials,packaging,optical fiber communication,integrated optoelectronics
更新于2025-09-11 14:15:04
-
Dopants Control of Electron-Hole Recombination in Cesium-Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Co-Doping Supersedes Mono-Doping
摘要： Using nonadiabatic (NA) molecular dynamics combined with time-domain density functional theory, we simulate electron-hole recombination in pristine and doped inorganic Pb-free double perovskite Cs2TiBr6. We show that replacing the titanium and/or bromine with silicon and/or chlorine extends the charge carrier lifetime. Importantly, dopants avoid deep traps despite they do not change the fundamental bandgap of Cs2TiBr6, they decrease the NA electron-phonon coupling and accelerate decoherence, arising from the reduced overlap of electron and hole wave functions as well as fast phonon modes induced by light dopants respectively, suppressing electron-hole recombination. More importantly, co-doping can reduce the formation energy of silicon and achieve higher doping concentration, potentially increasing the lifetime further. Our study suggests a rational strategy to reduce energy losses by co-doping in design of high performance all-inorganic Pb-free perovskite solar cells.
关键词： Co-doping,Electron-Hole Recombination,Mono-doping,Energy Conversion and Storage,Cesium-Titanium Halide Double Perovskite,Plasmonics and Optoelectronics,Time Domain Ab Initio Simulation,Dopants Control
更新于2025-09-10 09:29:36
-
Tunable Schottky barrier width and enormously enhanced photoresponsivity in Sb doped SnS2 monolayer
摘要： Doping, which is the intentional introduction of impurities into a material, can improve the metal-semiconductor interface by reducing Schottky barrier width. Here, we present high-quality two-dimensional SnS2 nanosheets with well-controlled Sb doping concentration via direct vapor growth approach and following micromechanical cleavage process. X-ray photoelectron spectroscopy (XPS) measurement demonstrates that Sb contents of the doped samples are approximately 0.22%, 0.34% and 1.21%, respectively, and doping induces the upward shift of the Fermi level with respect to the pristine SnS2. Transmission electron microscopy (TEM) characterization exhibits that Sb-doped SnS2 nanosheets have a high-quality hexagonal symmetry structure and Sb element is uniformly distributed in the nanosheets. The phototransistors based on the Sb-doped SnS2 monolayers show n-type behavior with high mobility which is one order of magnitude higher than that of pristine SnS2 phototransistors. The photoresponsivity and external quantum efficiency (EQE) of Sb-SnS2 monolayers phototransistors are approximately three orders of magnitude higher than that of pristine SnS2 phototransistor. The results suggest that the method of reducing Shottky barrier width to achieve high mobility and photoresponsivity is effective, and Sb-doped SnS2 monolayer has significant potential in future nanoelectronic and optoelectronic applications.
关键词： doping,two-dimensional,SnS2,optoelectronics,Schottky barrier width
更新于2025-09-10 09:29:36
-
Effects of Electron-Phonon Coupling on Electronic Properties of Methylammonium Lead Iodide Perovskites
摘要： Temperature can have a dramatic effect on the solar efficiency of methylammonium lead iodide (CH3NH3PbI3) absorbers due to changes in the electronic structure of the system even within the range of stability of a single phase. Herein using first principles density functional theory, we investigate the electron band structure of the tetragonal and orthorhombic phases of CH3NH3PbI3 as a function of temperature. The electron-phonon interactions are computed to all orders using a Monte Carlo approach, which is needed considering that the second-order Allen-Heine-Cardona theory in electron-phonon coupling is not adequate. Our results show that the band gap increases with temperature in excellent agreement with experimental results. We verified that anharmonic effects are only important near the tetragonal-cubic phase transition temperature. We also found that temperature has a significant effect on the effective masses and Rashba coupling. At room temperature, electron–phonon coupling is found to enhance the band effective mass by a factor of two, and to diminish the Rashba coupling by the same factor compared to T=0 K values. Our results underscore the significant impact of electron-phonon coupling on electronic properties of the hybrid perovskites.
关键词： Energy Conversion and Storage,Methylammonium Lead Iodide Perovskites,Plasmonics and Optoelectronics,Electron-Phonon Coupling,Electronic Properties
更新于2025-09-10 09:29:36
-
Systematic Investigation of Spontaneous Emission Quantum Efficiency Drop up to 800K for Future Power Electronics Applications
摘要： Future high-density power electronics applications may require optoelectronic devices for gate drive. Thus, a systematic study of optoelectronic material from 10 K to 800 K has been performed to understand the potential of the high-temperature operation of optoelectronic devices. The temperature dependence of the photoluminescence (PL) of InGaN/GaN multiple quantum wells (MWQs) was studied. The integrated PL intensity dropped by an order of magnitude at 800 K as compared to 10 K. The spontaneous emission quantum efficiency was calculated from the power-law relation linking the integrated PL signal and the excitation pump power. The validation of the traditional ABC model for solid-state lighting is extended to 800 K. This work demonstrates the feasibility of developing high-temperature optoelectronic devices, which have operating temperatures over 500 K.
关键词： high temperature photoluminescence,high temperature efficiency,power dependent photoluminescence,InGaN/GaN MWQs,power module,quantum temperature optoelectronics
更新于2025-09-09 09:28:46
-
Gate switching of ultrafast photoluminescence in graphene
摘要： The control of optical properties by electric means is the key to optoelectronic applications. For atomically thin two-dimensional (2D) materials, the natural advantage lies in that the carrier doping could be readily controlled through the electric gating effect, possibly affecting the optical properties. Exploiting this advantage, here we report the gate switching of the ultrafast upconverted photoluminescence from monolayer graphene. The luminescence can be completely switched off by the Pauli-blocking of one-photon interband transition in graphene, with an on/off ratio exceeding 100 times, which is remarkable compared to other 2D semiconductors and 3D bulk counterparts. The chemical potential and pump fluence dependences of the luminescence are nicely described by a two-temperature model, including both the hot carrier dynamics and carrier-optical phonon interaction. This gate switchable and background-free photoluminescence can open up new opportunities for graphene-based ultrafast optoelectronic applications.
关键词： ultrafast photoluminescence,gate switching,hot carriers,graphene,optoelectronics,two-temperature model
更新于2025-09-09 09:28:46
-
Two-Dimensional Electronics and Optoelectronics: Present and Future
摘要： Since the successful isolation of graphene a little over a decade ago, a wide variety of two-dimensional (2D) layered materials have been studied. They cover a broad spectrum of electronic properties, including metals, semimetals, semiconductors, and insulators. Many of these 2D materials have demonstrated promising potential for electronic and optoelectronic applications.
关键词： transition metal dichalcogenides,black phosphorus,optoelectronics,electronics,two-dimensional materials,graphene
更新于2025-09-09 09:28:46
-
Rationalizing Perovskites Data for Machine Learning and Materials Design
摘要： Machine learning has been recently used for novel perovskite designs, owing to the availability of large amount of perovskite formability data. Trustworthy results should be based on the valid and reliable data that can reveal the nature of materials as much as possible. In this study, a procedure has been developed to identify the formability of perovskites for all the compounds with the stoichiometry of ABX3 and (A′A′′)(B′B′′)X6, that exist in experiments and are stored in the database of Materials Projects. Our results have enriched data of perovskite formability in a large extent and corrected the possible errors of previous data in ABO3 compounds. Furthermore, machine learning with multiple models approach have identified the A2B′B′′O6 compounds that have suspicious formability results in current experimental data. Therefore, further experimental validation experiments are called for. This work paves a way for cleaning perovskite formability data for reliable machine learning work in future.
关键词： Perovskites,Energy Conversion and Storage,Machine Learning,Plasmonics and Optoelectronics,Materials Design
更新于2025-09-09 09:28:46
-
Switchable Two-Terminal Transparent Optoelectronic Devices Based on 2D Perovskite
摘要： A switch-like structure that can be turned on/off with photons is considered necessary for most optoelectronic devices, such as phototransistors and photodetectors. However, developing a single device whose photoresponse can be modulated without changing the measuring voltage or illuminating light is challenging, and yet to be achieved. In this work, a conceptually new 2D perovskite-based fully transparent two-terminal optoelectronic device that can be turned on/off with a short electric pulse without any further change in the measuring conditions, such as the illuminating photon or applied voltage is proposed and demonstrated. The device exhibits loop opening in the current–voltage characteristics, which is utilized to design the novel electrically triggered optoelectronic device. The photocurrent of the device can be modulated from zero to 2.2 mA using a simple voltage pulse. Further, a responsivity of 550 mA W?1 and detectivity of 2.16 × 1010 Jones are measured in the on-state. Potentially, the approach opens a new avenue for the design of two-terminal advanced highly transparent optoelectronic devices, such as smart windows and transparent image sensors.
关键词： optoelectronics,2D perovskite,transparent electronics,two-terminal devices,memristors
更新于2025-09-09 09:28:46
-
Desorption of Te capping layer from ZnTe (100): Auger spectroscopy, low-energy electron diffraction and scanning tunneling microscopy
摘要： The influence of the annealing temperature to desorb a protective Te capping layer of the zinc telluride (ZnTe (100)) surface was investigated. The surface reconstruction of the ZnTe (100) upon the removal of a Te capping layer grown by the molecular beam epitaxy was characterized by different methods. Auger spectroscopy brought out the chemical composition of the surface before and after annealing; the Low-energy electron diffraction (LEED) gave information about the crystallographic structure. The surface crystallographic configurations of tellurium Te (c (2x2)) and Te (c (2x1)) are confirmed by scanning tunneling microscopy (STM). Such a study reveals a phase transition from a rich-Te to a poor-Te surface as the annealing temperature increases.
关键词： structural properties,optoelectronics,Zinc Tellure,semiconductors,solar cells
更新于2025-09-09 09:28:46