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Publications
Ottman A Tertuliano; Philip J DePond; Andrew C Lee; Jiho Hong; David Doan; Luc Capaldi; Mark Brongersma; X Wendy Gu; Manyalibo J Matthews; Wei Cai; Adrian J Lew
High absorptivity nanotextured powders for additive manufacturing Journal Article
In: Science Advances, vol. 10, iss. 36, pp. eadp0003, 2024.
@article{tertuliano2024high,
title = {High absorptivity nanotextured powders for additive manufacturing},
author = {Ottman A Tertuliano and Philip J DePond and Andrew C Lee and Jiho Hong and David Doan and Luc Capaldi and Mark Brongersma and X Wendy Gu and Manyalibo J Matthews and Wei Cai and Adrian J Lew},
doi = {10.1126/sciadv.adp0003},
year = {2024},
date = {2024-09-04},
journal = {Science Advances},
volume = {10},
issue = {36},
pages = {eadp0003},
abstract = {The widespread application of metal additive manufacturing (AM) is limited by the ability to control the complex interactions between the energy source and the feedstock material. Here, we develop a generalizable process to introduce nanoscale grooves to the surface of metal powders which increases the powder absorptivity by up to 70% during laser powder bed fusion. Absorptivity enhancements in copper, copper-silver, and tungsten enable energy-efficient manufacturing, with printing of pure copper at relative densities up to 92% using laser energy densities as low as 83 joules per cubic millimeter. Simulations show that the enhanced powder absorptivity results from plasmon-enabled light concentration in nanoscale grooves combined with multiple scattering events. The approach taken here demonstrates a general method to enhance the absorptivity and printability of reflective and refractory metal powders by changing the surface morphology of the feedstock without altering its composition.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The widespread application of metal additive manufacturing (AM) is limited by the ability to control the complex interactions between the energy source and the feedstock material. Here, we develop a generalizable process to introduce nanoscale grooves to the surface of metal powders which increases the powder absorptivity by up to 70% during laser powder bed fusion. Absorptivity enhancements in copper, copper-silver, and tungsten enable energy-efficient manufacturing, with printing of pure copper at relative densities up to 92% using laser energy densities as low as 83 joules per cubic millimeter. Simulations show that the enhanced powder absorptivity results from plasmon-enabled light concentration in nanoscale grooves combined with multiple scattering events. The approach taken here demonstrates a general method to enhance the absorptivity and printability of reflective and refractory metal powders by changing the surface morphology of the feedstock without altering its composition.
Qitong Li; Jung-Hwan Song; Fenghao Xu; Jorik van de Groep; Jiho Hong; Alwin Daus; Yan Joe Lee; Amalya C Johnson; Eric Pop; Fang Liu; Mark L Brongersma
A Purcell-enabled monolayer semiconductor free-space optical modulator Journal Article
In: Nature Photonics, vol. 17, iss. 10, pp. 897-903, 2023.
@article{li2023purcell,
title = {A Purcell-enabled monolayer semiconductor free-space optical modulator},
author = {Qitong Li and Jung-Hwan Song and Fenghao Xu and Jorik van de Groep and Jiho Hong and Alwin Daus and Yan Joe Lee and Amalya C Johnson and Eric Pop and Fang Liu and Mark L Brongersma},
doi = {10.1038/s41566-023-01250-9},
year = {2023},
date = {2023-07-23},
urldate = {2023-07-23},
journal = {Nature Photonics},
volume = {17},
issue = {10},
pages = {897-903},
abstract = {Dephasing and non-radiative decay processes limit the performance of a wide variety of quantum devices at room temperature. Here we illustrate a general pathway to notably reduce the detrimental impact of these undesired effects through photonic design of the device electrodes. Our design facilitates a large Purcell enhancement that speeds up competing, desired radiative decay while also enabling convenient electrical gating and charge injection functions. We demonstrate the concept with a free-space optical modulator based on an atomically thin semiconductor. By engineering the plasmonic response of a nanopatterned silver gate pad, we successfully enhance the radiative decay rate of excitons in a tungsten disulfide monolayer by one order of magnitude to create record-high modulation efficiencies for this class of materials at room temperature. We experimentally observe a 10% reflectance change as well as 3 dB signal modulation, corresponding to a 20-fold enhancement compared with modulation using a suspended monolayer in vacuum. We also illustrate how dynamic control of light fields can be achieved with designer surface patterns. This research highlights the benefits of applying radiative decay engineering as a powerful tool in creating high-performance devices that complements substantial efforts to improve the quality of materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Dephasing and non-radiative decay processes limit the performance of a wide variety of quantum devices at room temperature. Here we illustrate a general pathway to notably reduce the detrimental impact of these undesired effects through photonic design of the device electrodes. Our design facilitates a large Purcell enhancement that speeds up competing, desired radiative decay while also enabling convenient electrical gating and charge injection functions. We demonstrate the concept with a free-space optical modulator based on an atomically thin semiconductor. By engineering the plasmonic response of a nanopatterned silver gate pad, we successfully enhance the radiative decay rate of excitons in a tungsten disulfide monolayer by one order of magnitude to create record-high modulation efficiencies for this class of materials at room temperature. We experimentally observe a 10% reflectance change as well as 3 dB signal modulation, corresponding to a 20-fold enhancement compared with modulation using a suspended monolayer in vacuum. We also illustrate how dynamic control of light fields can be achieved with designer surface patterns. This research highlights the benefits of applying radiative decay engineering as a powerful tool in creating high-performance devices that complements substantial efforts to improve the quality of materials.
Nayeun Lee; Muyu Xue; Jiho Hong; Jorik van de Groep; Mark L Brongersma
Multi‐resonant Mie Resonator Arrays for Broadband Light Trapping in Ultrathin c‐Si Solar Cells Journal Article
In: Advanced Materials, pp. 2210941, 2023.
@article{lee2023multi,
title = {Multi‐resonant Mie Resonator Arrays for Broadband Light Trapping in Ultrathin c‐Si Solar Cells},
author = {Nayeun Lee and Muyu Xue and Jiho Hong and Jorik van de Groep and Mark L Brongersma},
doi = {10.1002/adma.202210941},
year = {2023},
date = {2023-05-02},
urldate = {2023-05-02},
journal = {Advanced Materials},
pages = {2210941},
abstract = {Effective photon management is critical to realize high power conversion efficiencies for thin crystalline Si (c-Si) solar cells. Standard few-100-µm-thick bulk cells achieve light trapping with macroscopic surface textures covered by thin, continuous antireflection coatings. Such sizeable textures are challenging to implement on ultrathin cells. Here, we illustrate how nanoscale Mie-resonator-arrays with a bi-modal size distribution support multiple resonances that can work in concert to achieve simultaneous antireflection and light-trapping across the broad solar spectrum. We experimentally demonstrate the effectiveness of these light-trapping antireflection coatings (LARCs) on a 2.8-µm-thick c-Si solar cell. The measured short-circuit current and corresponding power conversion efficiency are notably improved, achieving efficiencies as high as 11.2%. Measurements of the saturation current density on completed cells indicate that thermal oxides can effectively limit surface recombination. The presented design principles are applicable to a wide range of solar cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Effective photon management is critical to realize high power conversion efficiencies for thin crystalline Si (c-Si) solar cells. Standard few-100-µm-thick bulk cells achieve light trapping with macroscopic surface textures covered by thin, continuous antireflection coatings. Such sizeable textures are challenging to implement on ultrathin cells. Here, we illustrate how nanoscale Mie-resonator-arrays with a bi-modal size distribution support multiple resonances that can work in concert to achieve simultaneous antireflection and light-trapping across the broad solar spectrum. We experimentally demonstrate the effectiveness of these light-trapping antireflection coatings (LARCs) on a 2.8-µm-thick c-Si solar cell. The measured short-circuit current and corresponding power conversion efficiency are notably improved, achieving efficiencies as high as 11.2%. Measurements of the saturation current density on completed cells indicate that thermal oxides can effectively limit surface recombination. The presented design principles are applicable to a wide range of solar cells.
Jiho Hong; Jorik van de Groep; Nayeun Lee; Soo Jin Kim; Philippe Lalanne; Pieter G. Kik; Mark L. Brongersma
Nonlocal metasurface for circularly polarized light detection Journal Article
In: Optica, vol. 10, no. 1, pp. 134-141, 2023.
@article{Hong:23,
title = {Nonlocal metasurface for circularly polarized light detection},
author = {Jiho Hong and Jorik van de Groep and Nayeun Lee and Soo Jin Kim and Philippe Lalanne and Pieter G. Kik and Mark L. Brongersma},
doi = {10.1364/OPTICA.468252},
year = {2023},
date = {2023-01-20},
journal = {Optica},
volume = {10},
number = {1},
pages = {134-141},
abstract = {Modern-day sensing and imaging applications increasingly rely on accurate measurements of the primary physical quantities associated with light waves: intensity, wavelength, directionality, and polarization. These are conventionally performed with a series of bulky optical elements, but recently, it has been recognized that optical resonances in nanostructures can be engineered to achieve selective photodetection of light waves with a specific set of predetermined properties. Here, we theoretically illustrate how a thin silicon layer can be patterned into a dislocated nanowire-array that affords detection of circularly polarized light with an efficiency that reaches the theoretical limit for circular dichroism of a planar detector in a symmetric external environment. The presence of a periodic arrangement of dislocations is essential in achieving such unparalleled performance as they enable selective excitation of nonlocal, guided-mode resonances for one handedness of light. We also experimentally demonstrate compact, high-performance chiral photodetectors created from these dislocated nanowire-arrays. This work highlights the critical role defects can play in enabling new nanophotonic functions and devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Modern-day sensing and imaging applications increasingly rely on accurate measurements of the primary physical quantities associated with light waves: intensity, wavelength, directionality, and polarization. These are conventionally performed with a series of bulky optical elements, but recently, it has been recognized that optical resonances in nanostructures can be engineered to achieve selective photodetection of light waves with a specific set of predetermined properties. Here, we theoretically illustrate how a thin silicon layer can be patterned into a dislocated nanowire-array that affords detection of circularly polarized light with an efficiency that reaches the theoretical limit for circular dichroism of a planar detector in a symmetric external environment. The presence of a periodic arrangement of dislocations is essential in achieving such unparalleled performance as they enable selective excitation of nonlocal, guided-mode resonances for one handedness of light. We also experimentally demonstrate compact, high-performance chiral photodetectors created from these dislocated nanowire-arrays. This work highlights the critical role defects can play in enabling new nanophotonic functions and devices.
Koosha Nassiri Nazif; Alwin Daus; Jiho Hong; Nayeun Lee; Sam Vaziri; Aravindh Kumar; Frederick Nitta; Michelle E Chen; Siavash Kananian; Raisul Islam; Kwan-Ho Kim; Jin-Hong Park; Ada SY Poon; Mark L. Brongersma; Eric Pop; Krishna C. Saraswat
High-specific-power flexible transition metal dichalcogenide solar cells Journal Article
In: Nature Communications, vol. 12, iss. 1, pp. 1-9, 2021.
@article{nassiri2021highb,
title = {High-specific-power flexible transition metal dichalcogenide solar cells},
author = {Koosha Nassiri Nazif and Alwin Daus and Jiho Hong and Nayeun Lee and Sam Vaziri and Aravindh Kumar and Frederick Nitta and Michelle E Chen and Siavash Kananian and Raisul Islam and Kwan-Ho Kim and Jin-Hong Park and Ada SY Poon and Mark L. Brongersma and Eric Pop and Krishna C. Saraswat},
doi = {10.1038/s41467-021-27195-7},
year = {2021},
date = {2021-12-09},
journal = {Nature Communications},
volume = {12},
issue = {1},
pages = {1-9},
abstract = {Semiconducting transition metal dichalcogenides (TMDs) are promising for flexible high-specific-power photovoltaics due to their ultrahigh optical absorption coefficients, desirable band gaps and self-passivated surfaces. However, challenges such as Fermi-level pinning at the metal contact\textendashTMD interface and the inapplicability of traditional doping schemes have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In addition, fabrication on flexible substrates tends to contaminate or damage TMD interfaces, further reducing performance. Here, we address these fundamental issues by employing: (1) transparent graphene contacts to mitigate Fermi-level pinning, (2) MoOx capping for doping, passivation and anti-reflection, and (3) a clean, non-damaging direct transfer method to realize devices on lightweight flexible polyimide substrates. These lead to record PCE of 5.1% and record specific power of 4.4 W g−1 for flexible TMD (WSe2) solar cells, the latter on par with prevailing thin-film solar technologies cadmium telluride, copper indium gallium selenide, amorphous silicon and III-Vs. We further project that TMD solar cells could achieve specific power up to 46 W g−1, creating unprecedented opportunities in a broad range of industries from aerospace to wearable and implantable electronics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Semiconducting transition metal dichalcogenides (TMDs) are promising for flexible high-specific-power photovoltaics due to their ultrahigh optical absorption coefficients, desirable band gaps and self-passivated surfaces. However, challenges such as Fermi-level pinning at the metal contact–TMD interface and the inapplicability of traditional doping schemes have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In addition, fabrication on flexible substrates tends to contaminate or damage TMD interfaces, further reducing performance. Here, we address these fundamental issues by employing: (1) transparent graphene contacts to mitigate Fermi-level pinning, (2) MoOx capping for doping, passivation and anti-reflection, and (3) a clean, non-damaging direct transfer method to realize devices on lightweight flexible polyimide substrates. These lead to record PCE of 5.1% and record specific power of 4.4 W g−1 for flexible TMD (WSe2) solar cells, the latter on par with prevailing thin-film solar technologies cadmium telluride, copper indium gallium selenide, amorphous silicon and III-Vs. We further project that TMD solar cells could achieve specific power up to 46 W g−1, creating unprecedented opportunities in a broad range of industries from aerospace to wearable and implantable electronics.
Koosha Nassiri Nazif; Aravindh Kumar; Jiho Hong; Nayeun Lee; Raisul Islam; Connor J McClellan; Ouri Karni; Jorik van de Groep; Tony F Heinz; Eric Pop; Mark L Brongersma; Krishna C Saraswat
High-Performance p–n Junction Transition Metal Dichalcogenide Photovoltaic Cells Enabled by MoOx Doping and Passivation Journal Article
In: Nano Letters, vol. 21, no. 8, pp. 3443–3450, 2021.
@article{nassiri2021high,
title = {High-Performance p\textendashn Junction Transition Metal Dichalcogenide Photovoltaic Cells Enabled by MoOx Doping and Passivation},
author = {Koosha Nassiri Nazif and Aravindh Kumar and Jiho Hong and Nayeun Lee and Raisul Islam and Connor J McClellan and Ouri Karni and Jorik van de Groep and Tony F Heinz and Eric Pop and Mark L Brongersma and Krishna C Saraswat},
doi = {10.1021/acs.nanolett.1c00015},
year = {2021},
date = {2021-04-14},
journal = {Nano Letters},
volume = {21},
number = {8},
pages = {3443\textendash3450},
abstract = {Layered semiconducting transition metal dichalcogenides (TMDs) are promising materials for high-specific-power photovoltaics due to their excellent optoelectronic properties. However, in practice, contacts to TMDs have poor charge carrier selectivity, while imperfect surfaces cause recombination, leading to a low open-circuit voltage (VOC) and therefore limited power conversion efficiency (PCE) in TMD photovoltaics. Here, we simultaneously address these fundamental issues with a simple MoOx (x ≈ 3) surface charge-transfer doping and passivation method, applying it to multilayer tungsten disulfide (WS2) Schottky-junction solar cells with initially near-zero VOC. Doping and passivation turn these into lateral p\textendashn junction photovoltaic cells with a record VOC of 681 mV under AM 1.5G illumination, the highest among all p\textendashn junction TMD solar cells with a practical design. The enhanced VOC also leads to record PCE in ultrathin (\<90 nm) WS2 photovoltaics. This easily scalable doping and passivation scheme is expected to enable further advances in TMD electronics and optoelectronics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Layered semiconducting transition metal dichalcogenides (TMDs) are promising materials for high-specific-power photovoltaics due to their excellent optoelectronic properties. However, in practice, contacts to TMDs have poor charge carrier selectivity, while imperfect surfaces cause recombination, leading to a low open-circuit voltage (VOC) and therefore limited power conversion efficiency (PCE) in TMD photovoltaics. Here, we simultaneously address these fundamental issues with a simple MoOx (x ≈ 3) surface charge-transfer doping and passivation method, applying it to multilayer tungsten disulfide (WS2) Schottky-junction solar cells with initially near-zero VOC. Doping and passivation turn these into lateral p–n junction photovoltaic cells with a record VOC of 681 mV under AM 1.5G illumination, the highest among all p–n junction TMD solar cells with a practical design. The enhanced VOC also leads to record PCE in ultrathin (<90 nm) WS2 photovoltaics. This easily scalable doping and passivation scheme is expected to enable further advances in TMD electronics and optoelectronics.
