12 results on '"Chao Zhao"'
Search Results
2. Lithium Deposition-Induced Fracture of Carbon Nanotubes and Its Implication to Solid-State Batteries
- Author
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Feng Ding, Xuedong Zhang, Yanshuai Li, Hui Li, Chao Zhao, Jian Yu Huang, Dingchuan Xue, Tingting Yang, Qiushi Dai, Jingzhao Chen, Congcong Du, Liqiang Zhang, Jun Zhao, Yongfu Tang, Stephen J. Harris, Ruyue Fang, Baiyu Guo, Sulin Zhang, and Hongjun Ye
- Subjects
Materials science ,Mechanical Engineering ,chemistry.chemical_element ,Bioengineering ,General Chemistry ,Electrolyte ,Carbon nanotube ,Condensed Matter Physics ,law.invention ,Stress (mechanics) ,chemistry ,Chemical engineering ,law ,Stress relaxation ,Deposition (phase transition) ,General Materials Science ,Lithium ,Confined space ,Short circuit - Abstract
The increasing demand for safe and dense energy storage has shifted research focus from liquid electrolyte-based Li-ion batteries toward solid-state batteries (SSBs). However, the application of SSBs is impeded by uncontrollable Li dendrite growth and short circuiting, the mechanism of which remains elusive. Herein, we conceptualize a scheme to visualize Li deposition in the confined space inside carbon nanotubes (CNTs) to mimic Li deposition dynamics inside solid electrolyte (SE) cracks, where the high-strength CNT walls mimic the mechanically strong SEs. We observed that the deposited Li propagates as a creeping solid in the CNTs, presenting an effective pathway for stress relaxation. When the stress-relaxation pathway is blocked, the Li deposition-induced stress reaches the gigapascal level and causes CNT fracture. Mechanics analysis suggests that interfacial lithiophilicity critically governs Li deposition dynamics and stress relaxation. Our study offers critical strategies for suppressing Li dendritic growth and constructing high-energy-density, electrochemically and mechanically robust SSBs.
- Published
- 2021
3. Hollow Silica Nanoparticles Penetrate the Peripheral Nerve and Enhance the Nerve Blockade from Tetrodotoxin
- Author
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Daniel S. Kohane, Tuo Wei, Claudia M. Santamaria, Bruce Wang, Andre Shomorony, Tianshe Yang, Tianjiao Ji, Qian Liu, and Chao Zhao
- Subjects
medicine.drug_class ,Bioengineering ,Tetrodotoxin ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Cell Line ,Silica nanoparticles ,chemistry.chemical_compound ,Nanocapsules ,Peripheral nerve ,medicine ,Animals ,heterocyclic compounds ,General Materials Science ,Anesthetics, Local ,Local anesthetic ,musculoskeletal, neural, and ocular physiology ,Mechanical Engineering ,Nerve Block ,General Chemistry ,Penetration (firestop) ,Silicon Dioxide ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Sciatic Nerve ,Rats ,0104 chemical sciences ,nervous system ,chemistry ,Delayed-Action Preparations ,Nerve Blockade ,Toxicity ,Biophysics ,Sciatic nerve ,0210 nano-technology - Abstract
The efficacy of tetrodotoxin (TTX), a very potent local anesthetic, is limited by its poor penetration through barriers to axonal surfaces. To address this issue, we encapsulated TTX in hollow silica nanoparticles (TTX-HSN) and injected them at the sciatic nerve in rats. TTX-HSN achieved an increased frequency of successful blocks, prolonged the duration of the block, and decreased the toxicity compared to free TTX. In animals injected with fluorescently labeled HSN, the imaging of frozen sections of nerve demonstrated that HSN could penetrate into nerve and that the penetrating ability of silica nanoparticles was highly size-dependent. These results demonstrated that HSN could deliver TTX into the nerve, enhancing efficacy while improving safety.
- Published
- 2017
4. Droop-Free, Reliable, and High-Power InGaN/GaN Nanowire Light-Emitting Diodes for Monolithic Metal-Optoelectronics
- Author
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Bilal Janjua, Boon S. Ooi, Jessica Eid, Chao Zhao, Tien Khee Ng, Munir M. El-Desouki, Rami T. ElAfandy, Idris A. Ajia, Iman S. Roqan, Ahmed Y. Alyamani, Aditya Prabaswara, Giuseppe Bernardo Consiglio, and Chao Shen
- Subjects
Materials science ,Silicon ,Nanowire ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,Nitride ,Epitaxy ,01 natural sciences ,law.invention ,law ,0103 physical sciences ,General Materials Science ,Voltage droop ,Diode ,010302 applied physics ,business.industry ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,chemistry ,Optoelectronics ,0210 nano-technology ,business ,Molecular beam epitaxy ,Light-emitting diode - Abstract
A droop-free nitride light-emitting diode (LED) with the capacity to operate beyond the "green gap" has been a subject of intense scientific and engineering interest. While several properties of nanowires on silicon make them promising for use in LED development, the high aspect ratio of individual nanowires and their laterally discontinuous features limit phonon transport and device performance. Here, we report on the monolithic integration of metal heat-sink and droop-free InGaN/GaN quantum-disks-in-nanowire LEDs emitting at ∼710 nm. The reliable operation of our uncooled nanowire-LEDs (NW-LEDs) epitaxially grown on molybdenum was evident in the constant-current soft burn-in performed on a 380 μm × 380 μm LED. The square LED sustained 600 mA electrical stress over an 8 h period, providing stable light output at maturity without catastrophic failure. The absence of carrier and phonon transport barriers in NW-LEDs was further inferred from current-dependent Raman measurements (up to 700 mA), which revealed the low self-heating. The radiative recombination rates of NW-LEDs between room temperature and 40 °C was not limited by Shockley-Read-Hall recombination, Auger recombination, or carrier leakage mechanisms, thus realizing droop-free operation. The discovery of reliable, droop-free devices constitutes significant progress toward the development of nanowires for practical applications. Our monolithic approach realized a high-performance device that will revolutionize the way high power, low-junction-temperature LED lamps are manufactured for solid-state lighting and for applications in high-temperature harsh environment.
- Published
- 2016
5. Facile Formation of High-Quality InGaN/GaN Quantum-Disks-in-Nanowires on Bulk-Metal Substrates for High-Power Light-Emitters
- Author
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Bilal Janjua, Aditya Prabaswara, Mohd Sharizal Alias, Boon S. Ooi, Nini Wei, Chao Zhao, Chao Shen, and Tien Khee Ng
- Subjects
Fabrication ,Materials science ,Nanowire ,chemistry.chemical_element ,Bioengineering ,Nanotechnology ,02 engineering and technology ,Nitride ,Epitaxy ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,law ,0103 physical sciences ,General Materials Science ,010302 applied physics ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Titanium nitride ,chemistry ,0210 nano-technology ,Tin ,Light-emitting diode ,Titanium - Abstract
High-quality nitride materials grown on scalable and low-cost metallic substrates are considerably attractive for high-power light-emitters. We demonstrate here, for the first time, the high-power red (705 nm) InGaN/GaN quantum-disks (Qdisks)-in-nanowire light-emitting diodes (LEDs) self-assembled directly on metal-substrates. The LEDs exhibited a low turn-on voltage of ∼2 V without efficiency droop up to injection current of 500 mA (1.6 kA/cm(2)) at ∼5 V. This is achieved through the direct growth and optimization of high-quality nanowires on titanium (Ti) coated bulk polycrystalline-molybdenum (Mo) substrates. We performed extensive studies on the growth mechanisms, obtained high-crystal-quality nanowires, and confirmed the epitaxial relationship between the cubic titanium nitride (TiN) transition layer and the hexagonal nanowires. The growth of nanowires on all-metal stack of TiN/Ti/Mo enables simultaneous implementation of n-metal contact, reflector, and heat sink, which greatly simplifies the fabrication process of high-power light-emitters. Our work ushers in a practical platform for high-power nanowires light-emitters, providing versatile solutions for multiple cross-disciplinary applications that are greatly enhanced by leveraging on the chemical stability of nitride materials, large specific surface of nanowires, chemical lift-off ready layer structures, and reusable Mo substrates.
- Published
- 2016
6. Lattice-Polarity-Driven Epitaxy of Hexagonal Semiconductor Nanowires
- Author
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Lifeng Bian, Bowen Sheng, Tao Wang, Ping Wang, Qingxiao Wang, Xiantong Zheng, Chao Zhao, Xixiang Zhang, Xinqiang Wang, Xuelin Yang, Xin Rong, Yongqiang Zhang, Zhixin Qin, Xin-Zheng Li, Fujun Xu, Ying Yuan, and Bo Shen
- Subjects
Materials science ,Indium nitride ,Nanowire ,Bioengineering ,02 engineering and technology ,Epitaxy ,01 natural sciences ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,0103 physical sciences ,General Materials Science ,010306 general physics ,Condensed matter physics ,business.industry ,Mechanical Engineering ,Hexagonal pyramid ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Crystallography ,Semiconductor ,chemistry ,Quantum dot ,Density functional theory ,0210 nano-technology ,business ,Molecular beam epitaxy - Abstract
Lattice-polarity-driven epitaxy of hexagonal semiconductor nanowires (NWs) is demonstrated on InN NWs. In-polarity InN NWs form typical hexagonal structure with pyramidal growth front, whereas N-polarity InN NWs slowly turn to the shape of hexagonal pyramid and then convert to an inverted pyramid growth, forming diagonal pyramids with flat surfaces and finally coalescence with each other. This contrary growth behavior driven by lattice-polarity is most likely due to the relatively lower growth rate of the (0001̅) plane, which results from the fact that the diffusion barriers of In and N adatoms on the (0001) plane (0.18 and 1.0 eV, respectively) are about 2-fold larger in magnitude than those on the (0001̅) plane (0.07 and 0.52 eV), as calculated by first-principles density functional theory (DFT). The formation of diagonal pyramids for the N-polarity hexagonal NWs affords a novel way to locate quantum dot in the kink position, suggesting a new recipe for the fabrication of dot-based devices.
- Published
- 2015
7. Monolithic electrically injected nanowire array edge-emitting laser on (001) silicon
- Author
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Pallab Bhattacharya, Arnab Hazari, Ethan Stark, Thomas Frost, Chao Zhao, Saniya Deshpande, Boon S. Ooi, and Shafat Jahangir
- Subjects
Silicon photonics ,Materials science ,Differential gain ,Silicon ,business.industry ,Hybrid silicon laser ,Mechanical Engineering ,Nanowire ,chemistry.chemical_element ,Bioengineering ,General Chemistry ,Condensed Matter Physics ,Laser ,law.invention ,Solid-state lighting ,chemistry ,law ,Optoelectronics ,Continuous wave ,General Materials Science ,business - Abstract
A silicon-based laser, preferably electrically pumped, has long been a scientific and engineering goal. We demonstrate here, for the first time, an edge-emitting InGaN/GaN disk-in-nanowire array electrically pumped laser emitting in the green (λ = 533 nm) on (001) silicon substrate. The devices display excellent dc and dynamic characteristics with values of threshold current density, differential gain, T0 and small signal modulation bandwidth equal to 1.76 kA/cm(2), 3 × 10(-17) cm(2), 232 K, and 5.8 GHz respectively under continuous wave operation. Preliminary reliability measurements indicate a lifetime of 7000 h. The emission wavelength can be tuned by varying the alloy composition in the quantum disks. The monolithic nanowire laser on (001)Si can therefore address wide-ranging applications such as solid state lighting, displays, plastic fiber communication, medical diagnostics, and silicon photonics.
- Published
- 2014
8. Hollow Silica Nanoparticles Penetrate the Peripheral Nerve and Enhance the Nerve Blockade from Tetrodotoxin.
- Author
-
Qian Liu, Santamaria, Claudia M., Tuo Wei, Chao Zhao, Tianjiao Ji, Tianshe Yang, Shomorony, Andre, Wang, Bruce Y., and Kohane, Daniel S.
- Published
- 2018
- Full Text
- View/download PDF
9. Surface Passivation of GaN Nanowires for Enhanced Photoelectrochemical Water-Splitting.
- Author
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Varadhan, Purushothaman, Hui-Chun Fu, Priante, Davide, Retamal, Jose Ramon Duran, Chao Zhao, Ebaid, Mohamed, Tien Khee Ng, Ajia, Idirs, Mitra, Somak, Roqan, Iman S., Ooi, Boon S., and Jr-Hau He
- Published
- 2017
- Full Text
- View/download PDF
10. Droop-Free, Reliable, and High-Power InGaN/GaN Nanowire Light-Emitting Diodes for Monolithic Metal-Optoelectronics.
- Author
-
Chao Zhao, Tien Khee Ng, ElAfandy, Rami T., Prabaswara, Aditya, Consiglio, Giuseppe Bernardo, Ajia, Idris A., Roqan, Iman S., Bilal Janjua, Chao Shen, Eid, Jessica, Alyamani, Ahmed Y., El-Desouki, Munir M., and Ooi, Boon S.
- Subjects
- *
LIGHT emitting diodes , *OPTOELECTRONICS , *NANOWIRES , *INDIUM gallium nitride , *GALLIUM nitride , *SILICON - Abstract
A droop-free nitride light-emitting diode (LED) with the capacity to operate beyond the "green gap" has been a subject of intense scientific and engineering interest. While several properties of nanowires on silicon make them promising for use in LED development, the high aspect ratio of individual nanowires and their laterally discontinuous features limit phonon transport and device performance. Here, we report on the monolithic integration of metal heat-sink and droop-free InGaN/GaN quantum-disks-in-nanowire LEDs emitting at ∼710 nm. The reliable operation of our uncooled nanowire-LEDs (NW-LEDs) epitaxially grown on molybdenum was evident in the constant-current soft burn-in performed on a 380 μm × 380 μm LED. The square LED sustained 600 mA electrical stress over an 8 h period, providing stable light output at maturity without catastrophic failure. The absence of carrier and phonon transport barriers in NW-LEDs was further inferred from current-dependent Raman measurements (up to 700 mA), which revealed the low self-heating. The radiative recombination rates of NW-LEDs between room temperature and 40 °C was not limited by Shockley-Read-Hall recombination, Auger recombination, or carrier leakage mechanisms, thus realizing droop-free operation. The discovery of reliable, droop-free devices constitutes significant progress toward the development of nanowires for practical applications. Our monolithic approach realized a high-performance device that will revolutionize the way high power, low-junction-temperature LED lamps are manufactured for solid-state lighting and for applications in high-temperature harsh environment. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
11. Facile Formation of High-Quality InGaN/GaN Quantum-Disks-in-Nanowires on Bulk-Metal Substrates for High-Power Light-Emitters.
- Author
-
Chao Zhao, Tien Khee Ng, Nini Wei, Prabaswara, Aditya, Alias, Mohd S., Janjua, Bilal, Chao Shen, and Ooi, Boon S.
- Subjects
- *
INDIUM gallium nitride , *QUANTUM dots , *LIGHT emitting diodes , *HIGH power lasers , *CHEMICAL stability - Abstract
High-quality nitride materials grown on scalable and low-cost metallic substrates are considerably attractive for high-power light-emitters. We demonstrate here, for the first time, the high-power red (705 nm) InGaN/GaN quantum-disks (Qdisks)-in-nanowire light-emitting diodes (LEDs) self-assembled directly on metal-substrates. The LEDs exhibited a low turn-on voltage of ~2 V without efficiency droop up to injection current of 500 mA (1.6 kA/cm²) at ~5 V. This is achieved through the direct growth and optimization of high-quality nanowires on titanium (Ti) coated bulk polycrystalline-molybdenum (Mo) substrates. We performed extensive studies on the growth mechanisms, obtained high-crystal-quality nanowires, and confirmed the epitaxial relationship between the cubic titanium nitride (TiN) transition layer and the hexagonal nanowires. The growth of nanowires on all-metal stack of TiN/Ti/Mo enables simultaneous implementation of n-metal contact, reflector, and heat sink, which greatly simplifies the fabrication process of high-power light-emitters. Our work ushers in a practical platform for high-power nanowires light-emitters, providing versatile solutions for multiple cross-disciplinary applications that are greatly enhanced by leveraging on the chemical stability of nitride materials, large specific surface of nanowires, chemical lift-off ready layer structures, and reusable Mo substrates. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
12. Lattice-Polarity-Driven Epitaxy of Hexagonal Semiconductor Nanowires.
- Author
-
Ping Wang, Ying Yuan, Chao Zhao, Xinqiang Wang, Xiantong Zheng, Xin Rong, Tao Wang, Bowen Sheng, Qingxiao Wang, Yongqiang Zhang, Lifeng Bian, Xuelin Yang, Fujun Xu, Zhixin Qin, Xinzheng Li, Xixiang Zhang, and Bo Shen
- Published
- 2016
- Full Text
- View/download PDF
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